Formula With UX1 (Page 1/1) P 88 GT AUG 28, 01:04 PM My Formula has a UX1 radio but invoice and RPO code is UM6. Car is original with 12000 miles- is this a factory fluke or did they have no UX1 when built? Any thoughts? Thunderstruck GT AUG 28, 02:35 PM Dealer or owner installed upgrade. jonrev AUG 28, 11:48 PM ^this. I put a UX1 in my Formula, they're very easily swapped.