My 2001Y 2.7T Tiptronic is AMD remapped to 307bhp, and I'm very pleased with it and them. I've had a couple of problems with the car, almost certainly not a result of the remap, and they were really helpful, always willing to talk on the phone or to have a look if I whizzed it up to them. I get 19mpg average and it is all town or fairly hard driving. Better car than the 4.2 apart from narrow body and no V8 sound!
Can be expensive to run, but no more than most other 300BHP 2 tonne cars. And it doesn't look like anything which means you can leave it and it should be there when you return!!!!