Personally I prefer Impco, it's cheaper and easier to maintain, but concerning quality, I cannot confirm which one is better.
The temperature (~70 C) is nothing special, remeber, that the regulator is very close to the engine.

You can replace the entire LPG installation to IMPCO, but in my opinion your problem rather lies in LPG quality, not the fuel/LPG system.
Simply clean it more often, replace the filters and membranes, check the valves and LPG hoses.