This probably has been discussed before, but I just had the micrometer out and checked the inlet of the GEN II M62 and found it to be 62.xx MM.
I then checked the outlet of the TB and found it to be 59.40 MM.

If you can find a shop to open the TB up 2.5MM you'd be seeing about a 5% (or more) flow capability from the TB, and more boost. Combine with a 2.2 or 2.3" SC pulley, non cracked and ceramic coated exhaust mani'* and you could really feel the extra power no doubt.

And now you're going to recalculate based on throttle plate diameter, which is actually the biggest restriction?

http://www.bonnevilleclub.com/forum/...ighlight=story



57.85mm on the plate. You can see all the dimensions you just measured here too, other than the inlet of the SC. As long as it'* bigger than the plate diameter, there'* not much to gain (not 5% certainly).

It wouldn't hurt to smooth out the TB-SC transition, though. Enough to justify the cost? I dunno.