Good to know Marshall. No doubt that the rues should require padding that was manufactured specifically to be used as roll bar padding (not literally the pool noodles or home pipe padding). Upon more googling, that explains why some sites list ensolite as resilient and some as non, tho the majority of the places that list it as non resilient are sites that are repeating a rule spec.

Al, if they are looking to change the rules, can we lobby to only require the higher density stuff around the bars that could come in contact with your head?

*edit* Here's the SCCA wording...
I. ROLL BAR PADDING
Braces and portions of the main hoop subject to contact by the driver’s
or passenger’s helmet, as seated normally and restrained by seat belt
and harness, must be padded with a non-resilient material such as
Ethafoam (R) or Ensolite (R) or other similar material with a minimum
thickness of one-half inch.
*edit edit* Found this on a FSAE website. Same situation where the rules said non resilient, but then ok'd ethafoam and ensolite.
http://fsae.com/eve/forums/a/tpc/f/1.../m/61810772821
I actually contacted the FSAE judges about this rule becuase I wondered why they specifically listed materials to be non-resilient when the manufacture lists them as resilient. The response:

"We seem to be getting hung up on semantics, "resilient", "semi-resilient", "non-resilient", etc. We inserted the phrase "non-resilient" into the FSAE rules a couple of years ago to convey to the teams that we did not want to see rubbery roll bar and head restraint padding such as pipe insulation.

Yes, Dow does classify their Ethafoam as "resilient". However, over the years we have found from experience that it does a very good job as roll bar padding or for head restraints in our forms of motorsport, e.g. Formula SAE, SCCA Club Racing, Solo II and Pro Rallying.

Confor foam CF45 (Blue) is approved by the FIA for use as cockpit and headrest padding for F1 cars above 30 deg C and for sports cars. Below 30 deg. C, F1 cars have to switch to Confor CF42 (Pink). These cars can run at a little higher speeds than we allow Formula SAE cars to reach, and therefore need to meet some tougher standards. Confor is an excellent material that works in these applications.

As far as the "weekend autocrosser" is concerned, our Formula SAE rules are more stringent for car safety than those for SCCA Solo II. So you should have no concern that a car complying with our rules will not meet the Solo II or local autocross rules. You do not need to use "FIA Approved materials". You may if you wish, but it is not necessary.

We hope this answers your question. If not, please contact us again.

Rules Committee,
FSAE"