Are carbon fiber dash panels allowed? , you only mention "fiberglass"

The dash and all of the interior is covered in the rule above. You can replace it in whole or in part in any material.

DD , Front bumpers/spoiler , OEM turbo bottom pc which goes underneath extends pass the radiator bottom by about 4" . Basically its as deep as the bottom edge of fender. So any spoiler should be able to go that far back.

ITS spoilers are allowed to extend back under the car no further than the front edge of the front wheel opening. Greg F

Thats what I mean, turbo under tray goes back that far.

We'll adopt the suggestion by Greg and Ernie to allow the undertray to extend from the frt of the car back to the frt edge of the frt wheel opening.

Can a non-OEM undertray be used?

In reading the above, I still can't tell if aftermarket front bumpers (under the header panel) are allowed. Bill Comat what's on your car? Also, since turbo fenders and header panels are allowed, what about the turbo bumper and support?

I have a fiberglass 'Turbo style' front on my car that replaces the bumper, lower valence/air dam. Please see the pertinent rule from the 2010 Cup rules.

8.1.6 Body / Chassis / Interior
(g) Spoilers and air dams are free providing they do not exceed maximum factory body width by any amount, maximum factory body length (not including the bumpers) by more then one inch or maximum spoiler height of the vehicle by more then 6 inches. Stock bumpers may be modified or replaced with non OEM material, providing that they are not relocated. Aftermarket rocker panels are permitted and cannot extend more then 1 inch out beyond OEM panels at any point and 1.5 inches down.

To clarify, the undertray from the frt of the car to the opening of the frt wheel well can be made of any materials.