it costs very little to just bore it out and get a new plate for your current tb...buddy of mine paid 70 for his, but also if you startout with a larger bore you can get it bored out larger than as opposed to a smaller diameter bore TB, example would be a tb that is 54mm, it can be bored out to like 58mm but if you start from 58 you can go higher..see what I am saying..
Milan