I purchased a 94 DX a few months ago and was looking for some advice on whether it would be worth is to swap to a DOHC. If so, I am aware of the bolts ons for the DOHC. I want to go N/A because i do not simply have the patience to screw around with a turbo.

My question is how much of the harness has to be swapped?

What is the maximum amount the head can be shaved?

Does anynone know of any performance bottom end parts ex. crank, pistons, rods?

I have a 5sp. do the axles have to be changed?

I just want to build a car to beat my friend's sentra spec v. Any advise would be helpful.

 

Going turbo will be much easier to beat your friend;s sentra.
Honestly it will be cheaper in the long run, but if yu really want to go NA thats great.
The bottom end would be more than strong enough on a BP. The Miata has higher compression pistons than the pro, so thats a start.
T0da makes alot of stuff, though its quite pricey, but the quality is top notch.
You've got the f series gear box in your DX. First gen LX models are quite plentiful, your easiest bet would be to find an LX at the junkyard. Get the engine, trans (G series tranny=stronger), axles wiring harness and ECU. After that its almost a plug and play operation.
I believe the SOHC harness can be modified, but if you can find an entire LX to scavenge parts from, you yould be best off with that route.