Hahaha... it really depends on your insanity. Hahaha.... Pardon me, I did not modify my engine to the max.... I just wanted to see how the engine looked like on the inside. Hahaha.
Seriously, it all depends on your budget. How much are you willing to spend? After spending some money for modification, will you end up sleeping outside the room or beside your bike? Remember that modifications always require a lot of serious research and thought. How hard are you willing to drive your bike? Are your ready to experiment? Are you willing to accept the consequences of experimenting? Sometimes, things don't go as planned and then kaboom! Hahaha... Are you willing to accpet that then spend again? Another thing is choosing a trustworthy and QUALIFIED technician or mechanic. One may be a good mechanic but also lousy when modifying engines. Ask around...ask around well. TAke notes and write them down then study them carefully before deciding on what path to take.
If you are after reliability, don't go for the extreme. Take the usual paths taken by most. Don't be swayed and NEVER RUSH in making decisions. Try to learn also from the experiences of others. Hehehe...
For reliability (tried and tested by most):
Step 1
Vixion camshaft
Vixion Valve Springs
Racing CDI (optional) -personal preference here but you might want to ask around (say, Traxxas or maybe Haen, etc)
Maybe an exhaust upgrade if you feel like it. (10-15%)
Racing CDIs with no limiters are also hazardous to the health of cast (stock) pistons. some of us end up blaming the CDI but it is actually the over revving that destroys the valve train and piston. A higher rev limit is better otherwise change to a forged piston.
Step 2
Block upgrade or reboring (ask around---Traxxas, Haen, etc)
Vixion upgrade to 150cc (reliable)
Still not satisfied?
Ask Haen or Traxxas or anyone else who has experimented, tried and tested on their own bikes. Hehehe
The decision is yours but modifications have their consequences. But careful modifications also increase efficiency and reliability. The resultant effect on reliability, efficiency and economy depends on how you ride your bike and maintain it...
Ride safe!
Regards
Blaster
Stock