Canadian Quadder, you absolutely need an aftermarket CDI! The increased RPM provided by the higher rev limiter makes a massive difference alone! It doesn't seem like the engine is being cut off so abruptly in the lower gears as it does with the stocker.

I'm running a big gun CDi and have been very pleased with it.

 

How many more extra revs do you get with yours, and I imagine this is one tough a$$ engine so it wouldnt hurt it any.
Checked my vavles again and surprise the intakes are extremely tight....

 

Straight from Big Gun's website:
Big Gun Rev Box DS 650 (03-06) Baja (02-06) Adds up to 3 horsepower once snapped in. Comes ready to install and go. Allows RPM to rev from 8000-8750 while advancing the timing for a bit more torque on the bottom end.

 

Does the 11.5:1 piston give you any real increase in power?