When Gus makes a hard U-turn in the Cougar, the front right hubcap flies off. But in subsequent shots, the car still has all four hubcaps.
The VIN shown for the Cougar is 17 digits long but before 1980, VINs were much shorter and the VIN has always been alpha-numeric to indicate such things as make, model, final assembly point, etc. Early VINs used the year as the first digit, then a letter for where assembled, a two digit code for body style, letter for engine and finally the production number (ex: if the number was 320 it was the 320th vehicle built with the same body type and engine from the same assembly plant). This Cougar would be closer to having a VIN of 4R93H25 meaning it is a 1974 Mercury Cougar with a 351 hp motor made in San Jose, CA.
Toward the end of the episode, boom mic visible in the reflection of the Santa Barbara police car behind Shawn as he is explaining how he would have disarmed the bomb if the bomb's manufacturer hadn't.
Shawn tells Pookie that the DA overturned Franks' conviction. DAs can't overturn convictions; only courts can.
At the end of the bomb scene, a regular police officer is seen picking up the deactivated bomb. it would still have been left in place until the bomb squad could've gotten there to confirm it was actually no longer a threat.