I recently purchased a CXL 2008 Enclave loaded with options and drove it 2000 miles on a trip. It drove nicely with one exception, transmission shifting. It hesitates badly when you manually press the accelerator while for example passing another vehicle. It seems to downshift nearly alright however when in Cruise Control except it always downshifts two gears and then comes back up one gear soon afterwards. This is annoying and probably over-stresses the engine. You would think that GM would get their new transmission downshifting properly and maybe a tad earlier when in Cruise Control but then have it downshift only one gear range so that excessive engine revving doesn't occur. I may see what the dealer has to say about this but I suspect they will defend GM and say that everything is operating as it was designed to even though there is bad manual downshifting hesitation and when in Cruise that downshifting 2 gears and then coming back 1 is as designed. I wonder!