I agree, you need to talk with each place you will be using it and find something that meets all their requirements. Drag strip, auto x, road course, Texas mile type events They could all require a different helmet spec and the last thing you want to do is buy one that doesn't meet the specs you need and not be able to use it.Might want to check regulations with any organization you'll be running with to see if motorcycle helmets are allowed. I would imagine they would require some form of Snell SA rating rather an M rating.
If you want nice graphics, do it the right way and get it custom painted.
I always recommend something from Arai's GP range, as well as Bell, Stilo, or Sparco. Arai makes the best product, Bell is good value for what you get, and Stilo and Sparco are both quality pieces as well. Fitment of the Arai GP line is second-to-none. It's what you see professional drivers in all major forms of motorsport from NASCAR to F1 wearing. I have a Sparco WTX-7 Air (pictured above) currently but previously used an Arai SK-6 (same as GP-6 but without the fireproof rating). The Arai just fits like a glove. The Sparco is every bit quality as the Arai but it doesn't fit me as nicely. It's also a slight bit heavier, even though it's carbon.
If you don't want shell out a ton of cash, go for something cheaper but still a car helmet. Motorcycle helmets are balanced a little different and offer a little different visibility because their use is different. I've never found them comfortable in a car/kart but I know some people who don't mind. Either way, the most important thing is the fitment of the helmet. If you can try a few on before you buy, that's best.
Not even room for a R paint job ?The HJC auto helmets are a good line as well. AR-10 is a pretty good choice.
I hate to self-promote but I'm shameless; I paint helmets. If you're interested, check out my website: www.oktanevisual.com I do all the design and paint.
Only note is that I'm booked up through December.