[mickmate]

Their are some options on the parts you mention. Kirkham offers a stainless frame, brakes are also optioned as Girling (original type) Wilwood, BIG Wilwood, Baer etc. Rear ends are effectively the same from one to another. Build quality can vary, you need to look at them in person and check that out. Fibreglass is easy to build up and sand down, aluminum needs to be pretty close on panel gaps etc and again has options on finish level.