coilovers in the back don't really work, since standard the spring and shock are separate. and you really shouldnt be putting the weight of the car onto the poor little upper shock mounts.

 

just buy a matched pair of springs and shocks for the rear.

 

AE86 brakes will definately not fit on ke70 struts.

 

the golden rule with the front end of a ke70, if you intend on doing any sort of major upgrade, throw the entire struts including springs, brakes, shocks....into the bin.

I think AE86 power steering racks have different mounts, but you might want to search on that. A manual rack will bolt in, I'm pretty sure.

 

I'm pretty sure I've seen reconditioned KE70 racks on ebay for just over $100. They're probably worth a look if you're putting this much into suspension.

Oh, and you might as well budget for new bushings and joints throughout front and rear. No point having nice shocks and the thing still clunks when turning and floats and speed. :)