Well, again, your making 105hp... Its strong as is. Even I'm pushing it close to 200hp with the 105hp spec components. Its fine.

Want strong, don't over build, but build well. Address the issues. Handle the balance shaft situation however you want, but do something. Top notch cooling is needed. Rod or replace the radiator and have the full shroud on it. Overheat it onc3 and you can expect problems. Do the head bold retorque procedure... honestly, the one thing you can benefit from would be ARP head studs.

Again, you make 105hp, unless you got a line on those headers used, it's a waste of cash. You'll gain 10hp at best? I agree, get gears, that you will def feel a difference. I,did.