it very advisable to not go beyond 400bhp with standard internals. They have been known to melt above this point
With a good tune and meth injection there are cars running way beyond this number
not saying they cant, just saying its melt down time
defo needs spacers.
Some past reports of powder coating wheels can be damaging so do a search. I think its down more to the temperature they are baked at.
Adam @ Z1auto a trader here can send wheels over from the US no probs and has done to quite a few members