The gear ratio is 10% different between the DX and the Si tranny. That doesn't necessarily translate to 10% slower/faster. To say a 10% difference in gear ratio translates to a 10% slower/faster car has got to be an oversimplification. The slower/faster calculation has got to be buried in things like torque, and h/p, the outer diameter of the tires, and the weight of the car using the tranny - among other factors... OH! and THE DRIVER, too! Which is a lot more important than ALL the rest.

There is apparently even a slight difference in the final drive ratio between the CRX Si tranny and the Civic EX tranny. If, in fact, I do have the Civic EX tranny (based on the info I've gotten here), then the difference is only 3%. That must mean that Honda considers the 3% difference negligible since Honda calls them interchangeable. A 3% difference in the final drive of the tranny can easily be tweaked out with a slightly smaller tire o/d. However, a driver's experience (or lack thereof) can make a larger contribution to the overall speed of the car.

We are talking about auto-crossing these cars, eh? Or are you guys bracket racing or "drag" racing? To me, straight line racing with 4-bangers provides limited entertainment, but to each his own. In my mind straight line racing is for American muscle cars. That's just me.