Hey i just bought my first 1990 300zx na 2+2 from my uncle for $700

its a fixer upper it has 188,xxx miles. Im going to get a cat back megan racing exhaust for it

i wanted to know what type of aftermarket parts can i add that are ca street legal? I also was wondering how much it would cost to put another na engine with lower miles in it. Also how can i take off the tint from the back windows. I know you guys have herd this 1,000 times but i just love this car and want to rebuild it to have it for years to come because when im driving cars pull up and want to race and i give them a run for there money but i know i can smoke em if i put in the right stuff. (Plan on getting a tt but after i help pay for my wedding) thanks for the help