If I bought an electric car in Texas and took the credit in Colorado because the non-resident Colorado TT questions never asked where the car was registered. OK?

respond to their questionnaire.  if you don't they will deny the credit.  they will probably do so may do so anyway because the vehicle was not titled in CO

.  QUALIFYING VEHICLES, TRAILERS, CONVERSIONS, AND DEVICES

There are both general and specific requirements for a vehicle, trailer, conversion, or modification to qualify for the

credit. Credits may be claimed only with respect to vehicles or trailers that meet the following criteria.

? For purchases or leases, the vehicle must be new and not previously titled or registered in any jurisdiction.

? In the case of conversion, the conversion must be EPA certified.

? The vehicle or trailer must be titled and registered in Colorado or base plated in Colorado if registered via IRP.

? The vehicle must have a maximum speed of at least 55 miles per hour.

? The vehicle, trailer, conversion, or device must qualify under one of the categories listed in the table below.

Colorado titling and registration

The vehicle or trailer purchased, leased, converted, or modified must be titled and registered in Colorado or, in the

case of a truck or trailer registered under the International Registration Plan (IRP), base plated in Colorado. The

purchase, lease, or conversion of a new vehicle or trailer qualifies for the credit only if the vehicle or trailer is titled

and registered in Colorado in the time and manner prescribed by law. The purchase or lease of a vehicle previously

registered in Colorado or any other state or jurisdiction does not qualify for the credit. For conversions of or the

installation of aerodynamic or idling reduction technologies on used vehicles, the vehicle must be titled and

registered in Colorado at the time of conversion or installation.

I can't say whether or not TT asked the right questions so as  to deny the CO credit,  if you think TT did not  you'll have to file a claim to recover any penalties and interest.  TT does not cover the additional tax.