I've previously used these people to buy an exhaust system for a LWB Vitara 1.6, and I will shortly be using them again for part(s) for my LWB Frontera.
I found the Vitara easy to work on because of the height, and obviously the Frontera I would imagine should be the same or better. There are so many exhaust bays doing inferior work these days I think it's worth a little effort doing it yourself on a 4x4, whereas, apart from a back box, I would not work on a standard car exhaust.
http://www.buypartsby.co.uk/exhausts_di ... e=VAUXHALL
Remarkably good prices. Last one was a "Timax" if I remember correctly. eg: compare the 2.0 Sport price from here to the average £130 at an exhaust bay. If you have a towing bracket be prepared to have to heat and re-shape the tail pipe though on a new exhaust you fit yourself.
Tony.