No problems in terms of title and registration, but certainly the possibility of lower resale down the road. I always look at conversions like this (or 4-eye to aero nose and vice-versa) as something that hurts the value of the car.
Did just this very thing to my last Mustang. It was a GT, but got punched in the front end and was missing the side skirts as well as a few of the body mouldings on the drivers side (bought the car from a buddy for $500 that needed them for his car).
I had a complete 4-cylinder car sitting in the yard for parts and did the conversion. As stated...as long as the VIN states its a GT, then it's still considered one. A person can advertise it as whatever they'd like...but the VIN won't like. Never had an issue selling it.
No problems in terms of title and registration, but certainly the possibility of lower resale down the road. I always look at conversions like this (or 4-eye to aero nose and vice-versa) as something that hurts the value of the car.
Plus it's something as a buyer i'd want to know. If i looked at a 5.0LX for sale, and the VIN stated it was a GT. It would throw up a Red flag to me. Same with trans swaps, or engine swaps.