hey few questions.. my ac dont work dont care for it..! if i take it out will i get any perfomance gains or any benifit to engine?

cleanin my engine! it is soo nasty and grimy! what can i use.? i have this purlple power stuff was next to simplegreen but was 2 bucks cheaper... but how can i clean it.. any techniques?with out messin any thing up... last time i did it 2 years ago i covered the distrobutor cap and the battery but i ended up messin up the blower motor some how so no heat and i finaly just replaced it ..

rust!!! wut can i spray under the car to stop or help out a lil so rustin stop or any thing.. i heard ruberizin .. but wut is a cheap way?

G1 teg coupe yeah yeah i know old school still runnin strong with 250,000
D16A1