unwanted throttle blip on decelerating

SurfDog

I have an uprev tune done at zcargarage in San Jose but am about to re-tune for high altitude driving in Colorado.

two questions (one easy one harder)

1. Do I need to retune from my present settings at warm sea level, to cooler and much altitude higher driving??? (between work at 5,500 feet and my home at 9,000 feet). I feel like the computer will adjust, but really do not know.

I could easily replace the Valet map(#3) or stock map(#2) for a mountain map.

2. I have experienced numerous occurrences of the following: While decelerating in a right fairly aggressive downhill turn (engine braking), about two seconds after the downshift (with and without SRM) I get a little "throttle blip" and lose some of my engine braking. Could this be a VDC function? It is really annoying, and (as I am usually counting on the engine decel) has me hopping on my brakes (which is inelegant and maybe a tiny bit unsafe as it always catches me by surprise)

3. (bonus question) Anybody have a good denver area tuner they can recommend??

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09 6spd Berk CBE, JWT cams, ZSpeed CSC, Stillen (25 row oil, brake cooling, sways, gen3 CAI), Passport (9500ci), Quaife LSD, Z1 400 hp kit, ss lines, pads, rotors, clutch etc, Phunk's pan and fuel starve fix