that 2.5 will live a REALLY LONG life if it sees 3000rpm cruise on a regular basis, just keep oil in it and keep the coolant temperature under control, nearly bullet prof engine. I'm running the 2.3L turbo engine at 150hp or so as opposed to your 115ish hp and don't know what speed I cruise at (tach doesn't work right now) and it is fine. I'm running 35" tires (actually just under 34" tall) and 5.13 gears and it's a decent combo, wish they were lower at times though. I would lean toward 4.88's