hi there if i was you i would just do it the simple way the way you wanted to do it in the first place powder coating is very good but you cant really do it at home unless you have all the equipment. well any ways all you need to do is get some nitromors/turps and paint strip the original paint what is on the frame, any scratches on the frame just give a little rub with some sand paper, get some primer you ddon't have to use grey you can use loads of diffrent colours but grey is a good choice for black paint if you just want you bike to come out shiny just get normal mat black paint and spray it with lacker but if you want a nice glittery/metallic effect (looks amazing) get some metallic paint (his can cost more but its worth it ) step 1: paint strip the frame using nitromors or turps step 2: take some sand paper and sand the rough bits down step 3: spray the primer on 1-2 layers as it is only the base coat step 4: spray the paint on making sure the spray can is not to close to the frame 3-4 step 5: spray the Laquer on i would say 2-3 times but its up to you and that the way i do it i have recent seen and done this on two friends frame sand it has come out nice thanks hope i have helped (con)