Welcome. If the budget allows, go for some good coil overs. I did a comparison earlier in the week between 2 Sti 08's. Both have full whiteline suspension pieces although Gordon also has many of the subframe bushes. He has stock suspension and spings whereas I have KW variant three coil overs. I was surprised as how ride comfort didn't vary much at all with my current settings.

Gordon's MMS 3inch turbo back system was noticeable quieter than my Invidia TBE. But hey, I still love mine.