First impression to me is way too much fuel. If its bucking under throttle and when you let up it wants to accelerate, that to me means when you let off the gas the air:fuel is actually going towards something it can use instead of just raw fuel. Have someone drive behind you when you go WOT and see if its backfiring/blowing black smoke out.

Also, did this problem just arise or has it been like this since it was turbocharged?

95 Eclipse GS: 10.5:1, Crower 2's and MSII
186 WHP - 150 WTQ
14.697 @ 93.85 MPH......Gone, but not forgotten
99 420A Avenger: Given to my sister
99 GS OZ: Sold
03 Evo 8: Family Car with balls