1st gen baggin

il also be baggin my new project soon.r there any problem areas im gonna run into while doing it.i wanna build it to lay 20s all around.do i have to have control arms.what about for 18s?i was also thinkin bout where to buy parts.im plannin on buyin all suicidedoor.com parts.anything i should know b4 i get started would be most appreciated.