Cutting out at high boost
 

MY93 cuts out at max. boost , rev counter drops to zero simultaneously, accompanied by massive bang as unburnt fuel ignites, obviously ignition failure of some sort. De cat pipe fitted, exhaust gas temp sensor disconnected, think egt light comes on briefly at same time as cutting out. Cleaned boost solenoid to no avail.

coil packs, boost cut, fuel cut, earthing problem (check the earth straps and add extra ones from battery neg to the block and ecu)

Spark plugs???

Look HERE to establish what caused the CEL - Likely to be what JGM has said though tbh ;)
Cheers

My brothers my97sti had same problem b4.
Have you fitted boost controller? depends on boost level. it will cut the fuel off at high points. a fuel cut defender will sort it out.