New Race Cars -- Safety Equipment

Roll Cage

There are a number of crucial points relating to the roll cage.

Correct materials
ERW tubing is NOT permissible in new construction, only DOM is permitted. Chrome Moly is ok, but must now be the same dimensions as mild steel, which eliminates much of the motivation for using it. The fact that Chrome Moly is difficult to weld correctly should be enough reason not to think about it too much before deciding to use mild steel DOM.
Appropriate design
In the SCCA, the General Competition Rules are quite specific about such topics as permitted number of bends and location of mounting points. On occasion, I'll see a beautifully crafted, professionally built cage where the fabricator obviously hadn't bothered to actually read the GCR for comprehension. We don't have "Get Out of Jail Free" cards for these cages.
In particular, look at the limits on the number of bends in things like the front hoop braces -- there should be no more than two on a side.
Don't weld to rust. It doesn't work.
In fact, if this is even an issue, I question the wisdom of using the particular body shell as the basis for a race car.
Finishing the job
The GCR requires that all welds be completed; this includes the top sides of the gaps where the bars are close to the roof. Check before you bring your shiny new cage to tech, because we will.

FIA Seats should use FIA mountings where possible
non-FIA seats must have a sound back support
OE type toothed sliders (for adjustment) under the seats are usually pretty awful; don't use them if you have any way at all to avoid it. There are some adjustable FIA mounts that work ok. (what happens with toothed sliders is that you hit something hard from the back or front, and the force of the impact shears the teeth off and the seat comes lose. This failure can kill.)

Safety Harnesses must have SFI labels
Harnesses must be no more than 2 years old
When you get a new set, check the labels on all belts. Vendors have been known to commit "Oopsies" with belt dates, and you want to figure this out right away, not months later when the tech inspector checks your new-but-not-really-new belts out.
Shoulder belt mounting
Wrap the shoulder belts around a bar in the main hoop at shoulder height if you can, and make sure that the belts don't bunch up where they pass through the seat.
Spacing between the two belts can be critical, particularly if a HANS device is being used. SCCA rules recommend 4" to 6" spacing. The HANS manual specifies 3". If you are using a HANS, make sure you are doing what the manual specifies.
Lap belt mounting
Straight to the floor is best. The factory belt mounts are tempting, but usually are too far back.
Check for wear wherever the harnesses rub; if they fray, replace them
UV kills belts
If your car lives outdoors between races, worry about this. Fading of the dyes can be an indicator. This is less of an issue now with the two year rule.

Window nets must have SFI Label
Most window nets from stores specializing in circle track supplies are good nets, but lack this label, so check.
No date rule (unlike harnesses)
Do not mount net to door
The SCCA does not permit this.
Secure mounting is a must
use steel rods through the top and bottom for security. The purpose of this net is to keep your arm inside the car should a 'serious event' occur.
Do not modify the net
Making holes, etc, in the net invalidates the SFI certification.
Arm restraints are not a valid substitute for a net
If you are driving a tin top, you must have a net.

Some of these are more "things to consider with an older car".

Use correct materials
Some things are not permitted (like FM 100). Check the GCR before you buy. Be aware that there are vendors who will try to push "the wrong stuff" at you. Know your GCR.
Take care with nozzle placement. Different materials have different placement requirements. Make sure you understand the manufacturer's recommendation.
Take care with nozzle type. Different materials require different styles of nozzles, so changing what's in the bottle can have serious implications.
Check bottle by weight over offseason.
That's right, take it out and weigh it.
Check condition of pull and/or triggering mechanism over offseason.
Things break, rust, or wear out. During the fire is a bad time to find out.