Take a look at this thread regarding different MAFs. Being that your car is a 2000S, you might want to check on a couple of things:
need help with air/fuel mixture problems
When I added the 74mm TB, I got a silicone elbow that fit the new TB and replaced all of the stock intake tubing with aftermarket tubing from AirRaid. I was able to get rid of the Heimholz chamber (intake muffler) and improve the intake flow along with insuring that there were no vacuum leaks.