I'm looking at the SM4. Nearly got it months ago, but wasted my money on turbo parts I can't use until installing new management. I don't know how many times I've said "Stupid emanage! That thing has got to go!" every time it forgets the new rev limit, forgets the new injector size, changes the ignition timing adjustment by itself etc(I caught it in the act the other day while logging. Mongrel thing). Fixing my engine management is next on my list after the exhaust. Anyway Ray Hall here in Cairns is apparently a very good tuner, not cheap, but knows the product very well. A friend of mine has just had an SM4 installed in his R33 Skyline, so I'll catch up with him(not in my car!) and see how it's going.