Most show judges require that the car be fully open until after they inspect your car. For the NSX this means the front compartment as well as the engine compartment and trunk. If these areas are spotless you'll do well. A well detailed stock NSX is spectacular as is the modded one. Though the modded car will be judged for creativity, fit and finish. You should style your car in the way that makes you happy and don't worry what the judges think unless you are really all about winning car shows.
I go to these shows to support a charity, hang out with other car guys and learn about their cars. And to hopefully educate others about the car we all love. I also let some folks sit in the car to experience the view that we see when we drive the car. There's no better trophy than the look of awe on the face of some kid as he/she sits behind the wheel of a video game avatar.
Good info from LostBuckeye. The Autorama World of Wheels under the ISCA (International Show Car Association) has been the most official car show I've participated last year. I plan to be in it again this year.
You have to have the car open, hood, rear hatch showing the engine, trunk and they require that at least one door is open. That is why I'm still working on either finding a door prop rod or making one.
Otherwise most shows don't deduct points for not having a door open. I always leave the windows open too.
IMO to win Best of Show a car has to be very impressive. I don't know if a person need to buy lots of mods.
It seems like being an import/foreign car would be tougher to win. At least here in the Midwest where I'm at. Most shows are about American Iron. Some of the shows don't even have a foreign or import class.
I've won quite a few class awards. Normally Import or Foreign. But I have also done well in two seater Sports Car class (non-Corvette). The larger shows seem to have a separate class for Corvettes, which is good since there are so many, and so many very nice ones.
I do the local Coffee and Cruise, it's just fun to see the cars and meet up with other car guys & gals.
In last year's World of Wheels my 91 NSX placed second in the Foreign Sports class behind a very nice 1949 MG TC Restored Roadster. It was a nicer car.
Even though I have aftermarket wheels and West Wings ground effects and a few other small modifications, headers, Kenwood Stereo etc. I show it in stock. Most shows allow a few changes from stock and still be able to show it as stock.
If you cross over to a Modified class then it is a whole other ball game. Then you go up against lots of bling, custom paint, etc.
The main thing is "Clean, clean, clean." Very few shows I've been to check the undercarriage, but a few of the bigger one's will.
For me it seems the NSX engine bay stays much cleaner than cars with their engines in the front. Then again, with the NSX having a mid-engine, they have more openings to judge, the engine bay, under the hood and trunk.
It is tougher for me to win when I'm in classes with new cars. Mine is stock and has small chips in the hood. Most don't see them, but they are there and if you get close enough they are there.
I attend most shows for charity events. But there are a few that aren't, like the Last Fling Til Spring which is the largest single day car show in the mid-west with Monster Trophies (even though they still have monster trophies all the class awards are plaques now, they believe most people would rather have plaques), and the Autorama World of Wheels (plaques except Best of Show and a few other specialty awards).
I began showing the car because people around here never really get to see one up close around here. But there are more owners in the area now, but still it is extremely rare to see one of us out in the wild.
Actually at last years World of Wheels while I was cleaning up the NSX during the show setup, quite a few of the owners with cars in the show came up to me and asked what type of car it is, which surprised me car guys wouldn't know what an NSX is.
My car is nice but it isn't Best of Show nice. Maybe at some local shows I could stand a chance, but most go to American made cars, some very old and some not so old.
I did win a Sports car class last fall up against a couple of new Vipers. I was a bit surprised, since it is tough to win against an almost new car when your car is 22 years old, now 23, or when I go up against a restored car.
But I do it for the fun of it. I enjoy looking at the other cars and it can be very entertaining listening to the comments of the people checking out the car. So many look under the hood (they really seem to get a kick out of the spare tire being there) and get a confused look on their face wondering where the engine is located. Then somebody will walk around toward the rear of the car and then yell out, here it is and point down to it.
I also put an Auto Arts 1:18 91 Formula Red NSX and a 1:18 Revell NSX under the hood and I have a little Johnny Lightning red NSX that I painted the roof black to match my car in the coin tray. That doesn't get me any points with the judges I don't believe, but it sure gives the kids a thrill. I believe many of them get more excited about the models.
Good luck at winning Best of Show. (I'm thinking Hawaii would be more receptive to imports)
And ditto on letting kids or even adults sit in the car... the looks on their faces and excitement is priceless.
That's fine, one less thing for me to worry about carrying home 
