I have that exact same Wilwood front disc brake kit that I bought for my 59 2 door sedan. On the instructions, is says from 1960 and newer, but on the Wilwood site, it does list that same part number for 57-59 Ford cars as well. You can get the aluminum calipers in a few different colors (mine are black), and the rotors are also available solid or drilled /slotted, I chose solid. Like Larry said, I was suprised how heavy the box was, but other than the very light aluminum calipers, everything else is pretty sturdy & heavy. You CAN buy lightweight rotors and hubs, but I think this kit is more oriented for street and heavy race cars.Wilwood also make kits for these cars that have much bigger rotors and calipers for people that want that.
As for Summit vs Jegs, both are very far away from me, both have similar pricing, and free shipping, I typically buy from Summit, as they "spread the wealth" around, sponsoring NHRAs ET Bracket programs, and numerous race cars, both Professional and Sportsman. Jegs does sponsor quite a few race cars, but only for the Coughlin family it seems. And although I have never had any problems with Summit myself, I have heard from several people that did have an issue with parts they bought from Summit, the company seems to have an excellent reputation for correcting the problem. Gotta like that!
I do understand that Jegs does sponsor some race series, like Sportnationals and Super Quick, but those are all way too far away for me to attend.