As an update for future reference, I did this today. Recieved eBay replica twin loop during the week & had it fitted about an hour ago. Just did an axle-back on it. Fits perfect under the EK (this was a hatchback fyi). However, the one I got had a 4" cannon-style tip on it which turned out to be MASSIVE. We tried cutting the tip back as far as possible without riksing cracking it, but it was still just too wide & long & even if we got it fitted it would look ridiculous. So I ended buying a smaller 3.5" angled tip
from the guys who fitted the muffler. Looks like Alvis' tip:

Quote Originally Posted by Alvis View Post

By civica at 2009-09-28
After we got it fitted, it looked really good. Much better than the huge cannon tip. Once we were done, we started it up and it sounds AMAZING. It's very deep & not too loud. It's barely noticeable at idle & low revs, but opens like a beast when you accelerate, but again, not too loud. No raspiness or 'tinny' noises either. I'm very, very happy with how it turned out.

For anyone considering this in future, but not looking for performace and/or are on a budget, I highly recommend it.

eBay link to the Twin Loop I used: http://www.ebay.com.au/itm/Universal...item3cc57891fe