I've just bought a MY99 uk impreza turbo that has a full decat japspeed exhaust system on it but the back box seems very low and quite loud, I'm in 2 minds whether to keep it on the car or change it for something better fitting and quieter, anyone got any views? A mate has offered to swap me my exhaust for his off his wrx classic which is a decat system with a Prodrive back box

 

I had one on mine, it does sit low but i never had a problem with it scraping. My car is only 30mm lower than standard though.

Was loud but i wrapped the downpipe and center section and it stopped a lot of the in car resonance, which helped. could try some sound deadening in the boot which again will stop the resonating.