Sounds like a problem I had after 6000rpm under higher boost - turned out to be 2 things: 1. too large a plug gap (running 0,6mm now with a MSD setup. 2. rotor phasing.
I know your engine doesn't run a dizzy, but check your crank angle sensor (trigger angle) and if you've set it up for rising or falling edge trigger, and the coil charge time. Mine also felt like the engine would lit a rev limiter.