#1 Get a Rule Book, many answers.
#2 yes, there are few of them out there.
#3 you could run in Production Mid/Mini Pickup or Modified Mid/Mini Pickup (see Rule Book)
#4 there are different size engine classes based on total displacement, you could have a 4Cyl 2.3 one meet, and 5.7 V8 the next, different records to beat.
#5 I highly reccommend a roll cage, terry has one, he didn't mention it.
#6 Welcome to Landspeed Racing