I've got a mkV GT sport TDi, love the car. Awesome on fuel and still have enough power to overtake easily/have some decent spirited driving. The torque is great, comes on from almost as soon as you take your foot off the brake/onto the go pedal. It peaks early around 2,250rpm but you can pull right through to 4,000rpm which is where the power (125kw) peaks.

Bluefin do tunes for these which are quite decent, and well priced. I believe this should bump it up to around 147kW/420nM which is well into V8 territory in terms of torque.
Here: http://www.gccorp.com.au/automotive/...roducts_id=346

All of the forester guys rag on me about it, but i don't care. Diesel is cheaper than U98 petrol....

EDIT: I'm taking it (standard) to a skid pan day next weekend, can let you know how it goes compared with my old XT forester.