So, after swaping from 3:54 to 4:10's the speedo is off about 20". I figure no problem swap the gear @ the x-fer case. NOT! electronic... 91 suburban. They say i need to change/reprogram something called the DRA? Digital ratio adapter? Behind the glove box? Anyone been there, done that? The 1 guy who knew of this at a Speedo Shop also said I'd need to convert from a 7 pin (if so equiped) for a 14 pin? I don't do electronics well! but the gear change sure was sweet! In a word.. HELP!