I highly recommend using Eastwoods Ceramic chassis paint. 2 part paint and extremely durable and chemical resistant. I believe it's every part as good as powder coating and easy to shoot at home.
I would power coat everything I can except the springs . I would just clean the with wire brush and sand paper , the paint or POR15 them . Retro Jim
Here's the thing that has always bugged me about POR-15. By the directions, it just seems like a lazy way of doing it. According to their directions, it seems it works better if you are too lazy to clean off the rust. I just don't like the concept of it's use. If I was to blast apart a front end to clean and make pretty, I would just blast everything but the springs, powdercoat, maybe chrome the spring or paint it to match the powdercoat. Done.
It is the chemical reaction with the rust that makes it work. Not that hard to understand. That's why it is useless on clean bare steel.
Definatly go by these directions when painting CLEAN BARE METAL!!!! I did not know we had to do this and i took my frame down to bare metal with wire wheels and stuff. Painted it with POR 15 let it dry for days and it PEELED RIGHT OFF!!!! We explained what happened to the nice people of POR-15 and they gave us another gallon for free for our trouble. It was our fault though. We followed all the steps the second time and it worked fine.