According to the guy who made the LM1, he says you should mount the O2 sensor at least 18 inches past the turbo.
We tried tuning an SR20DET with the sensor mounted right behind the turbo and it read crazy readings... we had the car all out of whack until we realized the sensor was getting too hot. (800+ celcius)
The LM1 needs the RPM sensing cable to read RPM, without it, you can only datalog voltages and A/F. You don't need the Aux Box ($500 thingy) unless you have an old school engine and no sensors built it.
My favorite thing about the LM1 is the outputs. They are PROGRAMMABLE to anything you want them to be within 0-5volts. I haven't seen any other wideband on the market that does this.
That means you can display your A/F with any device that reads voltage. You can hook it up to a $30 A/F gauge and tweak it to read dead-on accurate. You could also just output to a voltmeter, like I do. I use the Apexi turbo timer which displays O2 sensor voltage. I programmed the Lm1 to read A/F correctly on the Apexi timer, and no need to put anything else on my dash. The box sits inthe glove compartment, and never comes out.
I run the other output to my Tec3 for datalogging on there.
In friends cars, I've hooked these up using the RPM sensing cable, and datalogging A/F, RPM, MAF voltage, Boost, and TPS. It works great for tuning like this.
If you don't need all these features, hold out a bit and get the new model thats coming out... it will be the stripped down version and very cheap by comparison.