Considering getting an STi backbox cos they look good and arent too loud. I dont want an exhaust that is too loud, how loud are they? I do not want boom or resonance on the freeway. My MY00 is currently standard. How much extra power should it give and any improvement to lag?
I miss my full Scoobysport on my old car since it was much more responsive but was too loud.
Is there only one type of STi exhaust for an MY00? The Subaru STi Japan site lists them as being very expensive.

Keep a look out for a Prodrive badged backbox. In my opinion they are a good compromise between a Scoobysport and Standard.

I've got an STi BB on my MY99 wagon, chose it because one big outlet looks better than those two pee shooter size ones on the std BB. Not much more sound and not really any more power, but it does have a nice shiny stainless steel end !