I got a pair of Vipers that I use for, ahem, track days only (they're marked 'for competition use only'), yes indeed, I'd never even dream of leaving them on for road use, absolutely not, no sirree, etc.
They seem fine to me - they not the sexiest or most expensive, but they were offered to me for £50 for the pair so I had them. Nice noise, no obvious problems and they pop and bang on the over-run like a great big poppy-bangy thing.
I have heard stories about them, though, that say they fall apart like a cheap watch, but mine have endured at least ten thousand miles of neglect and are fine.
Mind you, I though mine sounded nice until I pulled up alongside a TL thou with a very pretty set of carbon fibre Termignoni's - the only way I can describe the wonderful noise it made was to say it sounded like a cross between a Motorhead gig and an earthquake.
Edited: Just checked a couple of sites, and I can't see either Termignoni slip-ons or race systems for a TL1000, so I'm now somewhat confused! However, there is a lovely pair of cans for the SP1, a snip at £710
http://www.bici.co.uk/bc/6466/118974/1/ ... austs.html
