Tuners
Paul
I assume that AMD are the guys up Oxford (Bicester) way, if so I have exeprience of them, been on their Rolling Road a few times! Geoff at AMD helped design the original Crypton Tuner but left Crypton as his real passion was for tuning cars, he is very very good, and determined to do a good job.
Have no experience of the others. Mapping is all a bit digital in my car world, most of cars I've had radically tuned have been on carb(s). Hey we could open an analogue v digital debate, carbs or mapped injection!!
You're right about bigger wheels/tyres, most people just slap them on, but they are a significant part of the the suspension package (this is something people like Prodrive get right, as can been seen from their manufacturer endoresements). Too many people think that big wheels/tyres gets betting handling, it instantly gets you more grip (in the dry) but usually screws up the handling as the suspension geometry gets screwed. Stealth is cool!
Mr Perceptive
BTW I have been a PHer for years but have a different handle!