pinguu

Im not great with mechanical stuff, just after some advice on changing the twin exhausts on my xj. ive had it 2 weeks now but wanting to smarten it up but not spend silly money. I was wondering if anyone can tell me if these would fit and would i need to have any work done ie re jetting if they do fit? http://www.demon-tweeks.co.uk/motorcycle/universal-exhaust-silencers/bike-it-universal-silencer-slashcut. Cheers