Hi Recently acquired 20V turbo in bbc. 43k miles. Was a bit disappointed with exhaust sound...very boomy, especially around 50mph. It was a stainless single box. Swapped in a decent standard 2 box system and now can't hardly hear exhaust at all...so much better. Less vibration also and seems to have gained power. A bit suspicious about 'special' exhausts. Much prefer the standard. Much more refined!
I'm usually a fan of keeping things standard, but certainly with the non turbo VIS the standard exhaust is very quiet so you don't get to fully appreciate the 5 pot burble. I had an exhausted tuned not to be boomy, but still sounds good.
Not sure if the one I replaced was Peco or not. It was a single box stainless. One cylinder, no markings. It was most noisy around 2000 yes but was definitely intrusive. An annoying boom is a novelty for a while but soon becomes tiresome to my ears - prefer to hear the hi-fi.