The fuel pump alone will not cause any major grief if it's installed properly with the oem sock on the bottom. There have been a few stories of fuel surge with the Walbro sock, maybe some one else can elaborate?
BTW have you changed or reflashed the
ecu? If not do you have any idea what the current air fuel ratios are under load?
If you answered no to both these questions then maybe its time to drive your "unexploded ordinance" slowly to a Workshop with a dyno and get a quick test done. Whats your symptoms now?