The 2008 and newer no roll bar,SFI stuff etc is for the AAA sponsored street legal events is what I have heard.Test and tune only.This was a reply I received when I asked on another site.NHRA Needs to post a full explanation as to what events a 2008 and newer Hellcat,ZR1 Vette etc can compete in.
The NHRA “Street Legal Style” events do not include the regular competition programs at most tracks, such as the Summit Racing Series. Nor does it include many special events that still follow regular NHRA/IHRA safety rules, such as Drag Week.

Street Legal Style events are on-track alternatives to illegal street racing . . . a “gateway” series to get folks used to coming to the track. The Street Legal exception does not mean that a Hellcat owner can just bolt on slicks and show up at any track at any time and get to run 10.80s in any event without a legal roll bar, SFI vibration damper, SFI trans shield or bellhousing, etc.