Why ?
Because even the smallest stroker kit (2.1 rather than the 2.15) gives a 30wbhp increase, the maps are already out for it. ITB's on the other hand, there are issue's with filtering (but you've read those right?) and mapping them, getting a decent idle isn't simple. It'll take lot of mapping, which isn't cheap an would bump the price up considerably to get them running well.
Plus, if at that point you still haven't got enough power you can add ITB's.
Alternatively you could go with the K24 bottom end, something like an IPS package, which would probably be quicker still.
Another alternative is the IPS inlet manifold which Ron claims makes more power than ITB's.
If after looking at all of those options you still think ITB's are the way to go, then do it, but on a personal note I wouldn't dream of buying ITB's until they are proven by a good few people, and that means outside of the UK too.
