Well, I just wasted a morning.
Went ahead and installed (well, tried) the Magnaflow cat-back on my 2002 Suburban Z71 (P/N 15665)

First, you CAN remove the stock system in ONE PIECE WITHOUT CUTTING IT IN TWO IF you a.) drive your front wheels on ramps (put it in 4LO so the front wheel are loked via the transfer case since you are lifting the back end up too!!! this way it won't roll off on you and squish you like a fly), get the bottom of the trailer hitch at least 45 to 50 inches off the ground (I have a 2.5 ton long frame floor jack (model42820) from Harborfreight Tools that is the best tool I ever bought. It will lift to 50 inches), let the rear axle hang free AND lower the spare tire (don't have to remove it, just lower all the way down)

Now guess what............the Magnaflow system doesn't fit my Z71 rear quarter panel mouldings. The 4" tailpipe was made to fit the standard Burb body without these Z71 mouldings.

The 4" tailpipe piece on the Magnaflow will severely rub and consequently melt that plastic moulding piece on the rear quarter panel. Also, the stock system comes out at a little angle and there is a small relief in the moulding. Unfortunately the Magnaflow system comes out at a right angle, so it doesn't match the relief. Even if it would fit in the moulding relief, it would still be too close.

Another issue I had with the cat-back is the front flange. On the stock system there is still about 1/16th of an inch clearance between the flanges when the cone in the center is fully seated and the bolts are tightened. On the Magnaflow the flanges would butt together before the cone in the center is really seated and seals. I wonder if that will give you an exhaust leak, but I couldn't test it since I took the system back off the Burb and hung the stock system back in there (which was easier than removing it.....go figure).

IMPORTANT TO NOTE:
I bought the system from Magnaflow's web store at www.hottexhaust.com

Called them and they are taking it back no problem or are trying to work something else out. They have EXCELLENT service!!! Friendly, responsive, concerned about you and helpful. Recommended!!

 

Should have just swapped in the Magnaflow muffler instead. The Tahoe/Suburban exhaust is big already. It's just the stock muffler that sucks. Part number is listed in my sig.