OK, i just picked up a 93 Z with an A4, with 160,000 miles. Got it for $1800, just needs a little paint and tranny work. Instead of building the motor in the car, I am thinking about buying a different motor and building it while i drive the car till it craps out. My question is besides the ECM, what would I need to add to change to go from the Speed Density to a MAF? Or am I thinking backwards and should keep the speed density? I am looking for around 375-400 whp after the build, and plan on using LE2 heads and cam, and keeping stock displacment. Is there an advantage to having SD or MAF?