You need to figure out what kind of differential the car has where you will get the spedometer because if they are the same, then you wont have to worry about it. I think that the 2.3-16 has limited slip 3.25:1 rear end ratio, but Im not positive. the 2.5 turbo has 3.07s I think.

Check on the rear end ratios.

Most spedo shops can make reducers and stuff to put on the back of the spedo head to match your rear end.

Austin