ive used a litre of the por 15 on my chassis and diff, and just under a litre of the por top coat to do the chassis and diff i still have to do all the control arms and bits and pieces so i have to get another litre i think i paid $90 a litre for the por 15 and $115 per litre for the chassis black por paint, you can store it but they recommend gladwrap under the lid and refrigerated so ive got the little bit of chassis black in the beer fridge i dont know if i would use there chassis black again i only did it because POR15 dulls off if exposed to sunlight so i got the top coat which is a satin but i dont think it looks as good, (the body might not go back on this year so if its out of the garage and in the carport i dont want it to fade)