When George leans on the painted Vista Cruiser outside the courthouse/police station, the fresh white paint rubs off on his suit sleeve, revealing the original blue paint underneath. Two minutes later when Ray picks up Carlos, Carlos uses his bare hand to close the car door through the window when he gets in, but no paint rubs off the car or on to Carlos' hand.
When Max is in the backseat of the car telling Carlos and Ray about the $5000.00 bail, he says it was for "grand theft on the car... Frank must have stolen it", but earlier, when Carlos returns from chasing Nick and tells Max and Ray he found the car, Ray says "He totaled my car?"...so it was Ray's car, not one that Frank stole.
When Ray is planting the last bomb on George's Crown Vic, he reaches up past the oil filter to the distributor. The only engines with that configuration are the straight sixes, which were never used in Crown Vics or any police-package. All police cars of that era have V8s, which have the distributor on top in the center, where it's impossible to reach from the below. Ford puts the distributor at the front; GM & Chrysler at the rear. Also, the distributor clearly has only 7 wires - one for each of the 6 cylinders, and 1 from the coil.
When Bill and George had Frank in the police car from New Jersey (while in Montana) Frank is told it's a short plane ride from Montana to New Jersey. If they drove from New Jersey to Montana, they would not have left a police department car from New Jersey in Montana to fly back.