Perhaps the most important questions have yet to asked. That would be "What size of garage do you have in which to play with your car?" I'm counting only flat empty floorspace not shared with bikes, mowers, wagons, and so on. ANNNDDDD.. "What time period in months or years can you devote this space solely to be the lovenest for your mechanical darling?" Further more... "What is your tolerance level for accepting hiccups, delays, no money, wrong parts, and so on?"
These answers can often dictate how to approach the first attempt at car building.