I have tillets in my car and yes if the seat isnt tilted back with spacers your head/helmet is pushed forward by the seat as the early ones were'nt really designed to be used with a helmet. This makes driving somewhat uncomfortable. To tilt mine back I have about 50mm of plastic kart seat spacers between mine and the runner, I've also got a foam (bag seat) insert to support my back. Simple and cheap fix. Regarding helmets, a snell race helmet isnt cheap, I know, I've just bought a new one, and isnt really required on a trackday when you arent wearing nomex pants. In your position I'd probably use the rock hard FIA cage padding and buy a good quality motorbike helmet, that fits well, that's the important bit. A motorsport helmet has a fire proof lining and generally have a smaller visor aperture, relative to a motorbike helmet. For what its worth, I have an ari gp6 and a hans type device as you cant be too safe.