Hi guys

I have a pred 90 that I am going to put a 54mm bb kit with high compression head (already have) prolly a 45 crank to mate up with it. I have a Hetrick intake coming, and will prolly keep the stock carb if possible. My goal is to get as much low end as possible. Which CDI is a good one that will work with reverse yet let it rev out more? We mostly trail ride and my son is interested in Harescrambles. I am looking to go the low cost route but give a nice performance boost as possible. Seemingly most of the pipes out there are mid to high end pipes so that is away from where I want to go as well.

Suggestions?