Turbo!
I bought my Apex in the fall of 2005, rode 800 miles stock and in jan of 2006 installed a stage 2 280hp MPI kit for $6k + extras, in the next two seasons of riding I put on just over 200 miles, trust me I will NEVER EVER run a SC again!!!! fuel boxes watering out, always playing with the fuel box!
I removed my SC kit sold it for 2500, and installed a turbo which is what i shoulda done in the first place.
I tell you they are more responsive out of the hole, but on top they hit a wall! and stop pulling.
With my stage 2 pullies running 100% race fuel (110 octane) I could pull my buddies MCX (260hp) by about 5 lengths, but after that 5 lengths it was all over he would blow by me. now you gotta remember that that was the old MCX kit, they are even more responsive now!
I highly recommend the boys at Quantum Velocity Performance in Red Deer! they know their s**t!
Hope this helps!
B