I was where you are 1 year ago. I bought an NA car and then a Turbo car. Through some very weird circumstances we ended up racing the NA car at the SF 250 and somehow won the NA class. Here is the thing, SCORE NA UTV does not get a lot of love, but it is a lot of fun. It is also a great place to learn. All of the NA guys in SCORE are grassroots guys and just banging it out. You have the top NA cars also racing in the Turbo class. After racing against the Turbo cars at SF, they are faster, but if you have a well set up NA car, you can do pretty well overall. We are going to continue in the NA class for a bit to get our SHIT together and then move to Turbo or Class 10 next year.
I would really recommend buying a complete NA car from someone that has raced it and knows all the issues. Get your team set up and do a lot of testing. Then get a solid builder that you can work with and trust and make a great platform. Race a couple of races and then decide what you want to do in 2017.
Just get out there and race...