turbo, cam, boost hoses, intercooler (hi rhys!), clutch, engine mounts, bushes as well as the usual array of fiddly sensors that go wrong are likely to fail on you unless they've been replaced recently.. and thats without even touching it with a remap.
Your 2.5k car could easily end up costing you 4k upwards in total if it's a lemon. Proceed with caution and get it checked out properly before you hand over any cash.