It's normal have a 5MT as well, and my engine revs high all day on fifth gear at 3600-4500rpms (70-85mph). These engines love to be reved high.
One thing you should always do is always check engine oil so it doesn't go low and change accordingly every 3000 or so miles depending on the oil you use.
Second things is check Coolant/radiator and fill accordingly so you don't overheat. (I don't have a leak but it does go low from time to time, so I add to the reservoir.)
Third is change transmission fluid according to manual.
FYI:The higher RPM's is where you will get the most torque and HP.
I rev often near/before redline often and these engine love it if you take care of the proper maintenance.
I'd like to add a 6th gear someday, I do recommend it, since the 6MT owners here love it.
I'm also down to do the 6MT Mod soon, I've been searching as well in the LA/OC area, let's get a mini group buy in our area and get some quotes on a deal? =)