Yeah, I thought you were supposed to decrease the gap with higher boost - its what I've just done. Mine (10 psi) bucked a couple of times aswell. Ive only just got new plugs/leads (NGK) with a 0.9mm gap instead of 1.05mm. Have only driven it once since so impossible really to tell if it will make a difference or not. I also went one stage cooler on the plugs.
Im sorry, I was playing with my gap at the time and realized that It was lower than stock, and It was a richen situation. So from stock gap, if you increase the gap, you will increase flame kernal, causing a larger flame,(more ability to burn all fuel mixture=more power) but it will be more prone to flame out under high boost pressures, ( the cutting out you feel), If that happens, reduce gap to decrease size of flame, it won't flame out as easy. Plug gapping has no exact science, you have to just kinda play around with differant gaps to see what works for your car. plug info
I was at the junkyard and seriously thinking of buying the intercooler off this volvo 760 turbo. Those intercoolers are the size of our radiators and have 3" inlet/outlet pipes to boost. If I werent selling my car in a month, I would buy that thing and make it fit in front of my radiator. Awesome size! No wonder those volvos were pretty quick.