Hydro Turf is tuff stuff !!
As long as you aren't abusing it... or leaving your boat out in the sun, and weather... it will last +10 years. If you get a darker color... it may fade a little... and when you scrub it, you may notice some small bits flaking off... but it's not decaying.
My 2001 Polaris Genesis came with Hydro Turf from the factory, and it still looks good. (and it was abused when I bought it)
As far as heat... yes... the dark colors can get hot... but since it's a foam product... it will never get so hot that you can't walk on it.
As far as the color match... contact them direct, and they will send color samples. But, my advice is to get a contrasting color. That way, you don't need an exact match.