Need Mods to Improve Power/Efficiency of Honda GX35 + Electric Starter & EFI Install

I’m an engineering student working on a vehicle project involving a Honda GX35 engine, and I’m looking for ways to improve its power and efficiency (efficiency takes priority). I also need to install an electric starter and convert it to an electronic fuel injection (EFI) system as a requirement.

My Goals:
Increase power and/or efficiency – Looking for performance mods (intake, exhaust, tuning, etc.).
Install an electric starter – Any kits or DIY solutions for this?
Convert to EFI – Are there small EFI kits that work with the GX35? Any recommendations on sensors, injectors, or controllers?

If anyone has experience with these kinds of mods, I’d love some guidance on what parts to use, what challenges to expect, and any resources that could help. Thanks!

Unfortunately I can’t help you with answers but I would be interested in finding out how much efficiency can be gained by switching to EFI. I would assume it would be Speed Density?
How will you measure the efficiency. Will it be a fixed load?