First time build - Steel Frame CNC Router

[JAZZCNC]

I have been doing some shopping around for quotes and would like some advice please.
For the linear components the following is what I got back:

Pay the £100 extra and get Hi-win from Fred Lee. Also don't need long carriages to cut aluminium the short ones work fine. I've got some Hi-win rails carriages (short) here that where fitted to my old router which cut nothing but aluminium for 5-6yrs and they are still good day fitted and they where second hand then.!!

Also, does £140 sound like a good deal for all the aluminium and steel plates (gantry sides, full z axis, bearing supports, spacers, etc)?

How longs a piece of string.? How can anyone tell you that without knowing dimensions and amount of aluminium.?