<font size="2" face="Verdana, Arial">www.focushacks.com gave a detailed explanation but is currently down.
you need a set of torq wrenches, some 12-24 hour epoxy, and ideally a dremel.
0.5. disconnect the battery terminals
1. disconnect the throttle and cruise control cable on the passenger side of the throttle body.
2. remove the air intake from the TB.
3. disconnect the power plug from the driver's side of the TB.
4. unscrew the TB using the torq wrenches
5. cover up the hole into the manifold with a lint free cloth or aluminum foil.
6. apply the epoxy to the back side of the TB (towards the trunk - don't be stingy) and let it dry overnight.
7. dremel out the lip on the backside of the TB so that the TB is round all the way around (don't worry, the part you need to dremel is obvious once you get it off and look at it). don't dremel beyond the diameter of the butterfly.
8. put it back together. note: the throttle cable and cruise cable require a bit of coaxing to get back on.
thats pretty much it. also when i was dremmeling i shaved off the fins that are in the tb. I highly recomend it if you dont have the cash for a FC tb. it only cost me $10 bux mainly cause i needed new sanding belts for the dremmel.
Vil - The epoxy acts like Bondo would for body work. The epoxy is to back fill in the area you're going to dremel out. If you didn't build up this side of the TB ( side closest to the firewall when installed ), then when you remove the bump on the inside of the TB, you'd end up making a hole across that entire side. Fill in with epoxy first, then when you sand the plastic away, you'll already have the hardened epoxy material there acting as the new wall for the TB in this spot. Just take the intake hose off the TB and look into the TB. It'll make sense what you need to do once you see it.