This is what I used and how I done my TB hope this helps others thinking of doing their's.

I would recomend that you buy a secondhand TB to port and polish just incase you make a mistake plus you will still be able to use your car and spend more time on perfecting the TB

First remove your throttle body (TB);
Remove the main feed pipe from the air box to TB, unplug the TB plug (black one top right) and undo the 10mm nut and 4 bolts holding the TB to the manifold. Remove the TB and cover the hole left in the manifold to stop any debris entering the manifold.

If you are using a secondhand TB remove your old one and try the S/H one first. (nothing worse than doing the work only to find out it didn't work in the first place!).

Tools:
here's what i used:

die grinder and rasps, Rasp's are availiable in most DIY shops and fit drills (wouldn't recomend using them it is very easy to get carried away and remove to much alloy)
Flap wheels of different grade's I used 40, 90, and 240 grit then moved on through wet and dry sand paper by hand right upto 6000 Grit :shock:

If you push down on the back edge of the butterfly valve on the TB as shown on the pictures below. the area that the valve sweeps is the area which should be left alone

Use the flap wheels to remove the alloy at the jaw of the TB to make it smooth taper towards the butter fly valve once it is as smooth as you can get it using sand paper move on to a t-cut this is where my custom tool came in handy

I covered a flap wheel in a polishing cloth and cable tied it on and used a t cut to make it as smooth as i could.

This is my TB fitted to my car

This is just a rough guide to how i done mine but hope this helps i you are thinking of doing your own.