I would be careful fella, what seems like a miss fire on boost specialy in 3rd 4th and 5th could also be underfuelling!! How long ago did you have it setup, might be the metering unit has difted out, or the EMFPA is dead?
I had this happen exactly as you described, changed everything (plugs, leads, coil, dizzy, etc..) and nothing helped till I changed the EMFPA! Wasnt fuelling correctly on boost, lucky I didnt melt piston