Best car for a full build?

Hi,

I've been doing HPDE events for a couple years and looking to invest in a dedicated track car. I’m as excited for the build as I am the drive, so having something that is fun and feasible to work on (i.e., minimal electronics) is as much of a priority as the driving experience. I plan to acquire a random used daily driver from someone, and run a full build from scratch as a project with my son.

I currently drive a stock G87 M2 6MT. I’m happy to end up in a lower power / lower weight situation, but I probably don’t want to go so far that direction as a Miata for example. Must be manual transmission.

I was debating an E36 or E46 M3, or maybe even a base model E46 3-series. If the latter, I could consider building for the spec series, which would be a nice bonus in case I ever want to get into wheel-to-wheel.

Related – should I try to keep the build street legal (not to daily drive; just to drive to the track), or abandon that idea and go all-out? I’m not completely clear on how much compromises are made to keep it street legal, but fine if I need to figure out a trailer situation.

You can assume no financial constraints (within reason!)

Appreciate thoughts from you all and love this community!