With a good 5th gear, overdrive is wonderful...
I have the mythical R200 with 3.36 rear gear. The transmission is a T5 with the G-Force Shafts and gears 1 through 4.
I run short tires Avon 23 /10.5-15 on all four corners.
When I first installed the G-Force gears I was only auto crossing the car, and really only used 2nd gear. When I started doing track days (Daytona and Sebring), I quickly discovered that 5th gear was horrible.
With the stock gears, 5th wasn't optimal but wasn't too terrible (3.35, 1.94, 1.44, 1.0, .67).
When I changed to the G-Force Gears, 1st gear was improved but 5th gear sucked (2.95, 1.95, 1.33, 1.0, .58)
First time at Daytona, I was redlining 4th gear by the time I came off the banking onto the front and rear straights, and the .58 5th gear would drop my rpms and torque too much to be useful. The .58 5th gear was horrible, so I pulled the transmission and took it to Astro Performance in Tavares, Fl and had them install the A5 5th gear (0.81). The difference was night and day. Overdrive went from a total buzz kill to being my Warp Drive...
If you get a transmission with a good 5th gear (TKX with .81 5th), then you'll be fine.
This is what the gear spread (speed versus rpm) looks like:
Here is what a full acceleration run looks like if you assume 0.25 second shifts:
The above uses numbers from my old dyno chart and the following inputs:
Dyno graph from my old engine (my new engine makes more power and torque):