Bingo,
That would be nice if all Calif. DMVs accepted the same laws. The one up here says it only applies to vehicles manufactured by a regular manufactured such as GM, Ford, & etc. Per their interpretation of the law, any special construction vehicle regardless of where it was built or previously registered has to have the SB-100 number or you will have your title pulled. I think our DMVs are as screwed up as the IRS as you can go to four of them around here and ask the same question and get four entirely different answers. So it is just safer to go with the SB-100.
Ron
