I promise that something has been monkeyed with or changed if you're pegging the stock boost gauge.
Try using a simple bicycle pump to test the WG operation directly - if the WG is somehow seized and not opening it could do this sort of thing on a stock setup. It should start moving the WG rod almost immediately with any pressure at all, like 2-3psi should show movement, it should be wide open by 6-7psi. If there's any washers between the WG actuator and the compressor housing, that's what's upping the boost and you need to remove those washers and start over again.
Past that, these other dudes suggested good things to check - gutted cats will usually see an increase in boost but I haven't seen a 7M-GTE so 'healthy' that it'd hit fuel cut from gutted cats alone, usually a turbo-back bellmouth downpipe and catless exhaust will see ~8-9psi with no other changes, and fuel cut is usually around 11.5psi.