After a lengthy thought process and the urge not to spend any money, I buckled and had the E46 remapped last week
The car in question was -

I bought this new in 2004 and I was very reluctant to mess around with it, it's maintained/serviced regardless of mileage. It's just clicked over 45k and is spotless so I had to think long and hard about modding the D!
After a 500 mile round trip with the Yorkshire Stripper down to Redneck county, I can report that this thing is a flyer
The torque is superb and pulls like a train, MPG is supposed to be good but rocketing it to 100 in a few seconds from 50 will dent the mpg until the newness wears thin
So far I'm happy






