Very interesting subject.... I have owned a 2000 xc se since I bought it new off the lot (hard to believe it is 8 yrs old!!). I still love the car, and I have done a few things to improve it over the years. However, the turbo was never designed with enough punch for the weight of this vehicle, and I have always wanted to find a way of getting it up to t-5 or R performance levels via ecu, turbo, downpipe, exhaust upgrades. The ecu is the simplest solution, although it doesn't do much for you on the high end/ high speed driving. A bigger turbo is the answer, but it probably gets more expensive than an 8 year old car can justify. I see it as foolish to put more than a few thousand $s into performance mods on these cars (I also see it as foolish that I bought the car new in the first place I must confess!!).

I assume a bigger turbo may require upgrades to the manifold, downpipe and exhaust in order to minimize pressure on the back end.

If you go down this road, I am definitely interested in your experience. Keep us in the loop.