I am using the MSD stand alone kit that comes with maps for many different configurations of LS engines already on the CD. My car uses a Z06 spec LS6 with the original cam and custom 1 3/4 headers as the only modification. I had to rebuild the supplied harness(was set up for front engine,my installation is mid engine with the intake manifold turned 180deg so some connections had to be lengthened or swapped side to side). Once the harness issues were sorted,it took me longer to load the CD on my laptop(I'm not too keen with computers) than it took to set up the system and fire it up! The system is user programmable,however I am concentrating on dialing in the chassis before tuning the engine for the last drop of power,so I will get it on the dyno sometime this season. Although it is still on the "base" tune, power and driveablility are excellant!! The kit lists for around $1800 and comes complete with ECM(about the size of 2 packs of cigarettes),full harness with relays and fuses,CD,tuning software, and interface cable. I am very happy with the system,especially for the price(MOTECs cost far more!)!
Dave D.