400 HP Boxster engine options???

[ksjohn]

I have a project in mind for a couple years down the road. I have a 99 stock Boxster. Love it! Great car! But it is just under powered. I want to buy a roller S and build a really fast car. I am thinking 400 hp would be a lot of fun! And I am not going to build an M96 motor to that level or spend $30K on it either.

I had originally considered a Chevy LS engine. Cheap, reliable and powerful! But have learned that it is just too big and you have to sacrifice cabin space to make it fit. I am tall so that is a no go option.

I also considered an Audi V8. Nice that it will bolt up to the tranny, but they don't appear to be that tunable nor that reliable. So probably not the best option.

I also considered a Subaru STI engine. They can make tons of horsepower, but again reliability seems to be a problem.

So what is left?? It would seem that many 4 cylinder turbo motors would fit in the car. An Audi or VW would probably mate to the tranny pretty well. But there have to be lots of other 4 or 6 cylinder turbo options that are reasonably priced and reliable that can make that kind of hp.

Anyone have knowledge of viable options?