well the guy seems to have a big intercooler, so maybe if we know what engine is in it we could help out a bit more, theres no reason to go overkill on brakes
yea i don't see the need for coilover in the rear unless you really need to upgrade, there are so many other rear suspension combinations that are proven to work better and all you lose is height adjustability
but if u think about the forces that this suspension system loads onto the area that was only designed for a shock mount, then it is too large, thats why it is recommended to reinforce the area around the shock mount