Afshin

I don't mean to imply that the Tokicos are not good. I had the somewhat standard tokico/eibach combination for many years and was certainly satisfied with them and think they're appropriate for a street car with occasional light track duty. You would get your money's worth out of them. I upgraded once I started to spend more time on the track. Suspension is mostly about balance and proper set up for each intended use, which is why it's soooo much trickier than increasing power/boost for example. When I first put my coil over set up it felt better (less lean and play..) but I also think it was slower around the track until I got to tune it some (change my alignment settings, camber, height, sway bar...) and then it finally performed better. So in short eibach/tokico is a reasonable start along with new bushings. I'm a fan of Bilstein's, but have not seen them for a stock ZX.

I'm using 280lbs/in front and rear springs rates and find the ride to be significantly better than I had expected. This is using a s13 stance coilover set up which I feel to be excellent dampers, that I modified for my 280 ZXT. This car is a little more set up for track use, but it's still driven on the street. Ride on regular roads/highway is excellent, gets reasonably bumpy on some city roads, but still acceptable and with sufficient travel to keep good tire patch contact on uneven roads. I also feel that the dampers affect the final ride more than spring rates (within a reasonable range).

I have also been using the superlites (same size pistons) with various Hawk pads over several years and have only noted minimal pad taper (approximately 1mm). I have not rotated the pads nor have I had any issues. Would buy them again.

What are you goals for the car (daily driver, weekend car, track ...) and what's your approximate budget?

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The adapter for the miata is for a 10/1 fitting. I was told and hence always thought that our cars also used 10/1 but I see that you said it is 10/1.25. If so, then I would be in error about the miata kit fitting our brake lines directly (I have not checked myself and was about the get the adapter from flying miata, so I can't confirm).

You can get the adapters from flying miata: http://www.flyinmiata.com/index.php?deptid=4539&parentid=0&stocknumber=14-76240 They stock the part now so you don't need to be part of the group buy anymore

It's because side wall stiffness affects the tire patch size, independent of weight and psi, that it would cause some inaccuracies. Since we can't measure the stiffness, we can't account for it. Just picture a run flat tire that will maintain a decent contact patch at 10 psi to a rated H tire at the same psi, it would significantly affect the weight estimate. I do agree that careful squaring of the cardboard to ensure accurate foot print measurement is likely the most important variable.

Cool idea! Temperature should not make at difference as it effects psi linearly and is accounted for in the calculation. The main variables that I can think of are tire side wall stiffness, distribution of pressure through out the carcass and measurement error in taking the actual foot print for each tire. Based on these we can expect it not be very accurate for total weight. However most variables are fairly constant between all four tires, so this method could potentially be very useful in figuring out corner weight percentage, notably for those with coilover set ups. I will have to try it.

I recently tried different potential fun and practical daily drivers (used 2004 to 2007 models) including some of the above mentioned one, here's my summary: WRX (2007) and mazdaspeed 3, thought the speed 3 was more fun and responsive (less lag) and handled better (in stock form) but the wrx AWD power delivery felt better than the FWD (which I'm biased against). THe wrx would need better springs shock and then should handle appropriate to its well designed chassis. Also test drove legacy GT (2006) and mazdaspeed 6. Liked both quite a bit but was not happy with gas mileage on legacy GT. Also thought the speed 6 handles better, at least with stock suspension. Comparing the speed 3 and 6, the 3 is a little quicker and spunkier (weight related) and the 6 is more refined, subtle, better chassis feel, suspension with AWD vs FWD which is why I preferred it. If you don't mind FWD I would definitely go test drive the speed 3. Comparing the legacy GT and WRX, I preferred the GT, all the fun but nicer interior, quieter and less of a police magnet. The wrx has advantage of greater availability and cheaper. ALso tried 2004 BMW 330i, liked it, did everything well as expected, nice balance but also less exciting. At the end of the day, I'm a turbo junkie. Also considered the Audi, but the reliability seems to be hit and miss. Many people like them but I know of enough who were unhappy with reliability). I ended up buying the speed 6 about 3 months ago and absolutely love it. Only thing I did not like was the power drop off after 5500 rpm (from electronic throttle programming from factory, the ecu starts closing the throttle past 5500 rpm even when pedal is to the floor) which I remedied with a COBB re-flash, making the car much faster (much more power at high rpm, not much difference in peak power). Same applies to the speed 3.

The mkIII intercooler is quite restrictive to flow. Turbo magazine had a review in the late 80's. I believe they found it to have close to a 3 psi drop at around 7 psi manifold boost. So you need to make 10 psi at turbo to get 7 out. That' quite a loss. This does not mean that it does not work, as plenty of people have used it successfully, including myself (I had a lightly modified mkIII). So if you're on a tight budget and already own it, its reasonable to use. However if you keep pushing the car, bigger turbo, more boost.... as many of us do, it would be worthwhile at some point to replace it with one of the newer cheap and fairly efficient aftermarket intercoolers that have become widely available over the last 5 years or so.

I also run a T03/04E 50 trim, 0.63 A/R with SDS fuel spark management. Will it does spool to good psi at reasonable rpm, it is really slow before that. In other words it start spooling late but then ramps up quickly. This is in comparison to my previous T3/T4 with a stock turbine. SO boost come on about 300 rpm later, but feels like its' off by 500 or more rpm. Using this configuration for open track events, i find the lag a little excessive and modulation of power in the 2500-3200 rpm range a little tricky. As such the car is much faster on the street, but not on smaller more technical tracks. This problem would only be amplified for an ATX set up. Of note, a main problem with my set up is that I'm still on stock cam and the mismatch with the turbo is quite noticeable so as the turbo comes to life by 2000 rpm later the cam chokes it (I have 3" downpipe, good intercooler....). I can feel that the turbo has so much more room to go on the topend as opposed to my previous one which did not want to go past 15 psi as effortlessly. In short, I agree with your thought process and would not lose sight of sacrificing top end power for a wider power band for any car aimed at autocross and would keep linearity of spool up in mind (to allow for proper throttle modulation) as well as what psi can be achieved at a certain rpm. In general, I would avoid larger turbine set ups more so than larger compressors (I wish I had spent the extra money for a BB turbo).