[tony20009]

If you genuinely need to achieve 350+ HP, you'll have to get a 335. Not sure what your objectives are as go the car's use, but the 328, and the HP it comes with or that it's boosted to via a tune is more than enough for daily driving.

It's not clear from your post whether you have a goal regarding HP achievement or whether you are using HP as a proxy that, in your mind at least, will allow you to reach some specific performance goal(s). Perhaps you can clarify your intent? You may then receive advice tailored to your goal rather than to a tactic that may or may not be the best way to reach that goal. It's not often that one seeks HP just for the sake of reaching a power output in and of itself, although there are engineers and researchers who do exactly that for the benefit of the academic pursuit and the learning that comes from having done it.