Profi Belts are great for almost every kind of racing. They are defined by the use of an RFR Cam Lock and feature a T-bar Anti-sub strap on 6 point models, and a straight sub on 5 point models.
Hybrid harnesses offer the best solution for Anti-sub strap comfort, as well as geometry. These harnesses are defined by the way the Anti-sub straps attach to the lap belt hardware, both spreading the load from the sub, as well as removing the T-bar from the limited real estate available in a racing seat. This gives an extremely safe and comfortable setup.
Traditional formula style restraints where the Anti-sub straps are routed through D-rings on the lap belts before wrapping around extended shoulder belt hardware.
SFI 16.5 harnesses are required by some sanctioning bodies, including NASCAR travelling series. If you are required to have a 16.5 harness, you'll find what you need here.