The book definition:
Registration plates: Any operator of a motor vehicle who shall willfully mutilate, bend, twist, cover or cause to be covered or partially covered by any bumper, light, spare tire, strap or other device or who shall paint, enamel, emboss, stamp, alter, ..... or add to or cut off any part or portion of a registration plate... or who shall display a number plate in other position other than a horizontal upright position, shall be guilty of a Class 2 Misdemeanor.
In other words, just place the damn thing in plain view where we can read it at least. And yes, you CAN get a ticket for those plates not in the horizontal upright position. Thats why you have to get the body work modified to put it on all kinds of crazy. It's because if it was meant to be read at an angle, we'd be walking around with our heads tilted sideways and you'd get that option when you bought your stinkin car.
ALSO, FYI of these:
Engine installed or body changed (more commonly known as engine or body swaps):
Whever a motor vehicle registered hereunder is altered or installed another engine in place of the original engine, the number of which is shown in the on the registration records, or the installation of another body in place of the original body, the owner of such motor vehicle shall immediately give notice to the Division in writing on a form prepared by it, which shall state the numbers of the new and former engine and registration. Whenever a new engine or seriel number has been assigned to and stamped upon a motor vehicle, the Division shall require the owner to surrender the registration card and certificate of title previously issued for said vehicle. The Division shall also require the owner to make application for a duplicate registration card and title showing the new motor or seriel number for the body....
Check with your local DMV on this one. But basically, if you installed a new engine or body on your vehicle (which has different seriel numbers than the one on your original registration of course), you are required to notify your DMV office and surrender your registration. They'll issue you a "duplicate" one, but it will have your new information on there. What this does, is helps track the seriel numbers from wrecked or stolen engines and body's. Most people should know that your vehicle's (usually boats, cars, trucks, vans, motorcycles, etc.) VIN can be found on a number of places. One of which is also imprinted on your engine. If you change it out to the point where that number is no longer present and you have a new one with a different seriel number, than you're required to report it to your DMV. Your registration will need to be updated.
But I know... I can probably count on one hand how many people in here have either done this or know about it. lol