[Dave at Pelican Parts]

I will speak to the 914, as that's most of what I know--

Not all 2270cc motors are built alike. There are some that are hand-grenades with no pin, and there are others that look like they will take years of normal use. Not sure about racing use.

The 2270 will put you into a "cubic dollar" class, where you will be a rolling chicane. (Or DFL at the autoX.) Unless you are only doing DE and the sanctioning body groups you by lap times or some metric that isn't "amount of improvement to the car" based.

914s are great little pocket race cars, but some parts are pretty hard to find now. There are people who have started making their own parts to sell (e.g., Mikey from 914rubber) but those are generally small-batch made as-they-can by an enthusiast with a day job. You'll want a cage with good bracing for anything serious in a 914, because their reputation as "flexy fliers" is not that far overstated.

Don't get me wrong, I love my 914, but as a dual-use track car it may not be the best choice.

I hear that Spec Box has pretty deep fields in So Cal, probably deeper than Spec 944. That would be something I would look hard at.

Or just buy one of the thirty-zillion Spec Piņata cars out there and call it a day...

--DD