I'm pretty sure you can get performance cdi's with a advanced spark and higher Rev lilimiter.
Well first off I'd have better luck getting more performance by engine swapping with a Teryx (same general driveline)
There aren't any performance parts for a Mule because it is basically a 4wd golf kart with a lift kit... it's meant to be all terrain unstoppable, not fast.
That said there are a few Mods that could be done to transfer some of the bottom end torque to top end power... but at what mechanical cost?
Do I need it to do 45mph... nah, but it would be fun until precisely the moment engine grenades.
Do I need it to do better than 20mph? Yes, people around here are absolute ★ssholes when it comes to their driving habit and general lack of competence behind the wheel... the latest offense was some di★khead passing me on the double solids.
Either way it has been stated everywhere Ive looked that any attempts to squeeze any significant gains only leads to the FD620D engine tearing itself apart.
I will end up doing exhaust work swapping the exhaust for something larger just off the header... probably 1inch ID true duals.
The intake breathes through the 2" tubing used for the rear roll cage hoop like a snorkel so I could disconnect that to free up the intake flow rate as well, it's not like I'm ever going swamping with it so it's not entirely necessary to have connected.
It has a fairly high compression by default, but swapping to a flattop piston and forged billet conrods would be preferable as well as a stiffer set of springs on the valves.