when i floor the thing and it comes on boost it sends a big bang and some smoke out the exhaust whats wrong with this thing

 

May be overboosting. Does it feel like the car wants to chuck you through the screen when it happens ?

 

does the car idle ok ? and just do this when on boost.. my guess would be the map sensor!!! or as said over boosting, check the amal valve is clicking when ignition is turned on.. if its not working it will just let max boost pressure.

 

could be many things as stated above over boosting incorrectly gapped plugs,incorrectly gapped/faulty cps/phase sensor faulty map sensor incorrect fuel pressure etc