I need some help

Alright well my car is having a bit of problems I get a pop/rattling sound in the exhaust when i put the car under load and it sounds like its coming from the manifold area. It gets louder the harder i push down the pedal

i took some readings with my diablo predator and my long term fuel trims are
+7 on bank 1 and +9 on bank 2

My baro is 30.5hz

I have no idea what the heck is the problem with the car is has absolutely 0 low end power heck even top end power seems to be down. Basically a 99 gt with catback exhaust pulled on me easy. Oh and im also running 94 octane gas so i dunno if its ping or not and im back on the stock tune and it still does it.

I have no clue what the problem is with the car so anything would help and i have no money for a new motor either so if she blows then im sol. oh and i pulled the plugs and they seem to be a little white on bank 2 but not bad at all bank 1 looked fine.

no the car does it just as much when its warm if not more and it idles perfectly fine too no surging what so ever.

any other suggestions?? Im gonna ask the ford tech guys on tuesday cause i have an appointment set up to get my gears installed then. But this is really making me mad its not as quick as it once was I have no low end power and it takes for ever to wind gears out. Like 2nd gear feels like an eternity trying to rev it all the way out to 5500.

oh and would an exhaust leak cause the low baro reading because pretty much all of these problems started to occur when i put the xpipe on. we had the exhaust welded and it was fine for a while and then the noise came back i tightened everything about about a week or two ago and it still made teh noise so do you think a bad gasket could cause those low readings like that? And i dont have a check engine light either