The small tick might be nothing more than a cracked exhaust header, which is a case of "when" not "if".
I will second the other guys in stating that changing head gaskets and cam will net next to nothing, especially considering cost. If you want more power, buy a bigger turbo, intercooler, and injectors/chip. If your car is running faster than 11.00, then buy a set of ported iron heads and THEN change cam/lifters and gaskets. But I will tell you straight up, that doing your planned changes is ill advised. I know Nick and myself have been building turbo Buicks for over 20 years. If you still want to do it, go for it, but my personal advise is to leave those parts alone for the time being. Get with a reputable shop/builder and seek their advice.