I have a 1996 k1500 burb with a 5.7 and the 4l60e w/corvette servo. Max towing on it is 5000lb and I just did a 400 mi trip towing a 4900lb trailer. It got there just fine, cruised the whole way in 3rd and never used overdrive, but on flat ground I could barley get to 55. I got to 59 once on a downhill! After the trip I looked on craigslist and I found a 2001 k2500 burb with a 6.0 and the 4l80e (i assume). Do you think I would notice much of a difference with the 3/4 ton burb or not? The weight didn't seem very unruly at all and seemed to tow just fine, except that it was completely gutless.

I am actually considering replacing the current burb with something that would do a better job. The extra added challenge is that my wife will use it as her daily driver and I have four kids, so a pickup is out of the question...unless somebody knows a cheap, safe, awesome way to add seats. Any ideas?