Halo seats are great.... but right side nets should still be considered EVEN with a head restraint system.... http://www.hmsmotorsport.com/docs/Why_You_Want_A_Right_Side_Net.wmv
If you wear a HANS device, it's a very good idea to run a RSN. An Isaac device has very good numbers in offset impacts, but a RSN is on the to do list in the RX7 as I think I'd rather hit it than the Petty Bar. I need to get faster as point bys are going to be a PITA with the RSN and the Petty Bar in the way!