you can use any turbo you want. find a turbo mani with the same flange, make it work. tuning will be up to you, cant use a mazdaspeed ecu(well, i wouldnt recommend it). lol it will spool instantly, but to answer your question this isnt commonly done so you will be pretty much on your own for advice. but yea, if your crazy enough you can use a caterpillar turbo.