I'll never understand people chasing more than 300/350bhp in a fwd car, IMO 300 is more than enough for uk roads, even track how often is the money spent on power going to benefit over weight saving or handling.
Drivability I think will be massively affected too (never driven 2l pushing 400bhp though)
If 4wd or larger displacement I could see the point in putting money towards those higher numbers though.
I have somewhere near 340 and always wish I'd stayed back at 280 and put money into handling.
Just my opinion though!