Ahh. I've replied to a thread you have posted in. Seems like vintage speed may not be the best exhaust for your needs!
I think the VS is a bit of a tricky one. Karlos who shows a strong dislike for them uses a large diameter 4-1 with phat boy, but is going for outright power. Sparkywig and that author of the post both had the standard sports muffler I believe hence some of the issues. I need to be carful with my choice as I have a young family 5 and 1 yrs and live in a sleepy village. A friend is running the super flow VS on his 1985cc and gets on well with it so I'm going to have a go in his van and see what it's like. It's a hard one to strike a balance on as exhausts seem so darn expensive.
I had the lower power one plus j-tubes on a 134hp 2020cc t1 that revved off the rev counter scale. It was not restrictive. It also didn't resonate at cruising speed like the 4:1 seem to. It was quite loud though.