It's OK. My car (300C SRT8) is way quicker/faster but the SS does get up and go when I ask it to. I'm kind of disillusioned with GMT800 reliability vs. GMT400's from the two SS's in the driveway. They're good trucks, but IMO, not *great* trucks. Limited sample size for sure, these are the only two I've really messed with so far.
Can't believe everything you read, but you can believe this - from personal experience, there are three lengths of leaf springs in GMT400-world. Blazer/Tahoe/etc. are one, Suburban is another, and pickups are the third. They don't swap. (I didn't have any 2dr Tahoes in the yard so I can't speak for those but I doubt they're different than the 4dr.)
According to Husky Spring, the Blazer/Tahoe/etc. are 27", Suburbans are 30", pickups are 32"
(Didn't bring C&C 2500/3500/3500HD models into this as they generally wouldn't apply. 3500HD are 3" wide leafs vs. 2.5" anyway and wouldn't swap even if the length was correct.)
Richard