Cat less headers and NH inspections
 

I am still in the research phase and planning to purchase one of the twins next spring.

Has there been any issues when you installed a cat less header when getting an inspection, I would imagine it would be an instant fail? Or does having the second cat further back help?

I would prefer a cat less header as they do make more power but also want to not ruin the environment and get one of couple catted headers on the market.

Been leaning towards OFT tune and FT86 Speedfactory catted header as the first mods.

Probably depends on actual shop doing inspection. I think the issue would be if you have a check engine light (CEL) on when getting inspected. OFT tunes disable the cat efficiency cel so at inspection it shouldn't matter what header you get. Nh doesn't do a tailpipe test today, just check for cel.
The dealer might pick up on the header swap but an independent shop would probably have no idea what stock looks like so as long as there is no cel on the dash it should be fine.
Running catless and probably increasing your emissions is a different story. Cats are relatively expensive and there for a reason, you know the manufacturers wouldn't put them in if they didn't have to. But that being said even an aftermarket high flow cat probably doesn't work as well as stock from an emissions standpoint. But without actually testing that's all conjecture.
So in summation, any header with an OFT should be inspectable, but not really sure if fully legal.

All shops are required to do a visual inspection to see if any emissions equipment has been tampered with. Some shops are more vigilant about this than others. I've had my car failed because I have a lot of stuff done including the header. Then there are some places that just plug in the computer and call it a day. My car doesn't stink though. I do have one cat in the front pipe and run e85 most of the time. Smells good.