Like many people I need to recover the rear deck on my 328 GTS, I have seen the original material available for a ridiculously expensive price. I can get similar looking material for very much less money, the trouble is, if I do the deck it won't match the roof. So my question is, how do you do the roof ? it has several deep recesses and bumps and what feels like hard foam underneath. Has anyone done the roof section, can you give advice ?