340 Piston to valve clearance w/RHS heads

The hyper pistons don't run hotter, the top ring is up higher so it gets hotter hence the larger ring gap. If it were my engine I would run the lightest pistons I could find hyper or not. And yes lighter pistons will make a very noticable difference in how it runs, how fast it revs, how it feel behind the wheel. If you can swing it the Scat I-beams are very light and very strong. Those and some light pistons that would be one heck of a reving engine. With hyper pistons that engine will last over 100k hard miles easily as long as you get that ring gap right.

All other things being equal, an engine with lighter pistons will out excellerate an engine with heavier pistons. It will out last it too.