I don't own a 05+ Gt but I have driven many of them because of my job and I feel a huge difference between them and my old 01.
The other day I went WOT through 3 gears on a stock 05 gt 5 speed many times.
He wanted me to diag a cutting out problem at the top of the gears WOT, also he said his shifter binds when he powershifts. Let me tell you I felt a huge difference, and my 01 gt had 4.10's a off road x, sct tune, K+N and flowmasters
the 4.10's in my old car made them feel about the same SOTP but comapring them with the stock gears it is night and day.