There belts not chains mate. I had mine changed at Vauxhall as i needed it doing asap as the tensioner got noisy and crapped myself. Cambelt and tensioner, water pump and aux belt and tensioner came to about £400. At the time my S plate was worth £4k and the engines went for £800+ plus fitting which was expensive due to the work involved. Forget about repairing after a belt/tensioner fail though as your talking a couple of grand to rebuild.

Ive had a few of each, 2.0, 2.5, and 3.0. 2.0 are crap and wouldnt pull the skin off rice pudding. The 2.5 are decent enough and the 3.0 obviously goes quite well once moving. They can keep up with UK subarus once rolling past 60-70 and thats been proven on numerous occasions.

My 2.5 elite would do 40-45mpg on a long motorway run with the cruise control on. Round town and i was lucky to get over 25mpg and was usually around 22-23mpg. The 3.0's are very similar and can very often be better than the 2.5 as the engines dont have to work as hard. Mine was auto which is FAR better than manuals in my opinion, if a little bit thirstier, maybe by 2mpg.

As said, heat exchangers, cambelts (kit), water pumps, worn suspension and bushes (due to weight), worn/snapped drop links, and uneven tyre wear, are the things to look out for. Also check ALL the electrics on the higher models like the elite and cdx as they can be expensive to sort. Check the xenon lights and self leveling suspension works too if its got it.