Personally, if you really want a Volvo with the 2.5T engine, I'd go for a MK1 Volvo S60 2.5T with 5 speed manual box, then start tuning it up.
You can find these for reasonable money - £2-3k
They are 210bhp stock, but a stage 1 remap will see 260bhp (same as the C30 T5, because the engine is near enough the same).
Big bonus with that engine in the S60 is the turbo can be swapped, whereas in the C30 the turbo is integrated into the exhaust manifold, which really limits your options for tuning.
Another bonus is the 5 speed manual that the S60 2.5T gets.... vs the 6 speed manual that the C30 T5 gets.... In the C30, 3rd gear is very annoying because the engine falls out of the power band right at the moment where you're "having some fun", whereas on the 5 speed box, 3rd gear is a little longer in ratio and gives you a better use of the engines torque. At least from what I've seen from acceleration videos.
So yes, having owned a C30 2.0-litre petrol and 2x T5, AND an S60 2.0T, I would definitely go for an S60 because they are just outright better cars, better built, better to drive, big fat wide stance, wider wheels... much better road presence etc.
