The Matrix/Corolla/Vibe/Celica (1ZZ engine) fuel rail is tucked in close to the engine with insulation around it. This is the first production fuel injected engine I've seen heat fuel. But, I'd have to say it'll work on some engine and not on others. Any engines designed close to the knock limit may not like warm fuel. So, its going to be one of those hit or miss things.
Check out post #27 here for pictures:
http://forum.ecomodder.com/showthrea...5.html?p=22861