If you are building your car to be street legal in Colorado here is the information you need to build it to meet state requirements. Pay attention to the windshield law as it is vague and doesn't actually say if it is required or not.
http://www.coloradodot.info/business/ru ... c_Code.pdfThe big difference is how you get it registered. Motorcycle, custom build/kit car, etc.. I know some people have just used the vin number for the car that their engine came from to complete the process. I am not sure how this is done... offroad guys do it a bunch. You can also register it in a county that doesn't require emissions to get around the whole smog thing. Its kind of hard to fail emissions in Colorado though.
Steps to Getting a Colorado Assigned VIN
The first rung is having the vehicle inspected by a law enforcement official. This official will also fill out a form DR 2704 which directs the emissions assessor on how to check the vehicle (this form is supplied upon inspection).
http://www.colorado.gov/cs/Satellite?bl ... inary=true
The inspection fee is $20.
Call your title and registration office for a referral list.
If the vehicle is a home-built or a kit model, you will complete a Colorado Assigned Vehicle Identification Number Declaration of Facts (form DR 2426) and then apply for the number by filling out the Application for Colorado Assigned Vehicle Identification Number (VIN) (form DR 2408).
http://www.colorado.gov/cs/Satellite?bl ... inary=true
The fee is a $3.50 fee for this service.
Once the number is assigned you will take it and the completed DR 2704 form to an emissions testing technical center operated by the Department of Public Health and Environment (DOPHE).
Passing the emissions test (if necessary) is the final step required to prepare the vehicle for titling and registration. From here, the process is pretty much the same as with other vehicles.hope this helps.