Is there a difference, without a doubt....how much varies from person to person as you can see. I was able to drive the 5.3 6spd, 6.2 eski 6spd, 6.0Hyhoe, 6.2 H2 6spd and a TBSS.all the same day back to back to back to back same route taken each time the difference between the tahoe5.3 and Eski 6.2 was not overly noticeable, but it was much nicer to drive with alot less busy shifting from the trans which equates to having more power to pull the inclines etc. Now jumping into the TBSS from the tahoe was a big difference very noticeable as it should be.
I did this comparo when I was first contemplating trading my current tahoe the only reason to was to update a year or two, but the only one that caught my attention was the TBSS which is too small for a family of 4 with 3 large dogs...so I kept what I had since it is built the way "I" want it, power is not an issue with my current set-up, but it is addicting and the reason I am doing a front-mount turbo.