That's grand if it's a track-only car and you always wear a helmet. If it's a road car i reckon it's worth paying a few quid for proper padding.
I wouldn't fancy whacking my head off a cage if i had a tip anyway.
Did you ever feel the right proper stuff that is ment to go on the bar that is at the top of the windscreen it is rock hard i felt it in the rocket bunny 666 car i dont understand how this is going to help you in an impact...