its been done a few times, just have a quick search for build threads in the projects/members rides area.. (hah! adam just beat me in the reply)
id dare say you'd have to make custom mounts for the box and motor.. smash the sr's onto the 4a's and weld away, if the motor sits out the bonnet it doesnt matter, street cred :cool:
or, bolt in option;
get a 4agze motor, remove the charger, buy a ebay manifold (or make one, or buy a *insert jap brand name here* manifold) bolt on t25/t28 dependant on your tolerance to lag, fit cooler, make pipes for exhaust / cooler.. upgrade injectors, turn boost up, drive to work with big grin
talk to some importers for prices on cuts
cheers
-brian