Out of curiosity what are the cost differences

Don't forget the recertification of parts . The freight costs can be huge as well as removing and reinstalling the components. My bell is now 5 years certified but the clutch set up is still every 2 years. Seatbelts every 2 years too. Freight was 180 to ship my clutch/flywheel assembly. Bell is 90 each way. Seatbelts 70 bucks plus freight. And as pointed out SFI suit which typically is thicker and heavier can be miserable on a hot day. Chassis certification money too.
Just part of going 9.9
Yep.fun to say I went nines...... but I'll never do it again.... unless I turn on a nitrous setup, intending to get tossed.