Ooh nasty, if its your manifold that has a hole a good welder could fix it, but if you need a few welds on different sections, labour could be a lot over here and it may be cheaper to upgrade. RS200 exhaust differs from the IS200 so sourcing it over here could be a problem. couture auto do some exhaust systems for the altezza, they could help you out.
ye ask to speak to ben or ask if he can give you a ring. you could also ask if he wanted to sell the one from the altezza they have there. 01 825 3949
tho ben aint around most days so he could end up ringing you at 7pm this evening to talk it over.