AE86 and EF Civic are popular for tuning in Japan and USA but it is very hard to find genuine parts for them in Japan. It used to be easy, not anymore. People look at Yahoo! auction or junkyard, but it’s impossible to find body parts, lighting and interior because Toyota and Honda stop selling parts for them. “Jyunsei Ryuyou” is key word for keeping ‘80s cars (jyunsei means genuine; ryuyou means divert), so it shows you want to keep genuine parts for these cars. For AE86, engine swaps are one of the most popular customizing style; you can see F20C, SR20DET, 2JZ or 3SGE but AE86 purists will say that an AE86 without a 4AG is not an AE86. Toyota put 4AG motor into Levin/Trueno and offered three model changes from ’83 to ’00: AE86, AE92 and AE111. Engine code is 4AG but Toyota changed spec that’s why AE86 motor make 130ps and AE111 can make 165ps. There is even supercharged 4AG for MR2 AW11 and Levin/Trueno AE92/AE101. There are so many parts for 4AG because this motor was available for 17 years but some transmission parts have become rare or Toyota has stopped selling them. That’s why some AE86 shops put Honda S2000 transmission into the car; all that’s needed is an adapter for connecting 4AG motor and S2000 transmission (only a few shops can do this). For EF Civic, many genuine parts can also fit EG and EK Civic, and DA Integra. Some Japanese EF owner put B16B Civic Type R motor and suspension into their car, so the ease of finding genuine parts is what makes EF popular in Japan and USA. Most important thing is to find a good mechanic who knows how to maintain these cars, which is kind of vintage now. I think you need.