the sr goes right in. same mounts but i would recommend getting new ones. the ka ones are probably in crappy shape.
you can use the stock t25 but they suck after a while.
a t28 is a great turbo and can do what you seem to want.
the t2871 is probably your best bang for the buck tho.
and worry about the swap before you start worrying about what upgrades to do. swaps are a big step so one at a time.
goodluck!
and +1 to research but i used to be the same way. lol