what is the best way to get more power from one of these motors? ive seen the carb kits and header kits but have read many reviews saying that they lacked any real adding of power? any thoughts on this and if u have done both the carb and header upgrade how was the performance after the installation?

The only way to improve the power of a small engine is to make it think
it's a big one, by getting it to move more air and fuel, bigger cam, valves,
ports, headers and EFI or carburetor are some of the ways to do this, but
remember you are starting with ~60 HP, so even if you get a 15% hp increase
you are knocking on a whopping ~70 HP, a good improvement, but probably
not going to really solve your thirst for more power.

There are other options, forced induction (turbocharger or supercharger) and
a 1.6L replacement, which will give you 80 to 95 HP depending on which
version engine you get (8 or 16 valve) but engine swaps come with their own
group of issues (EFI and computer on a 16V and electric fuel pump if you stay
carb and keep the 1.6L head, as there is no provision for a mechanical fuel
pump on a 1.6L 8v engine.

I thoroughly recommend forced induction, as you can roughly double your
stock HP output, but then again you have issues with where you live in some
cases because of smog checks.

Good Luck
Wild   

Only drive downhill