It's easy if you have the tools and know what you are doing, it takes more than anyone is going to tell you here on the forum but is not that hard, start using the r32 complete wiring harness only changing the 4th and 6th injectors pins
(rb25 igniton is different.), use r32 ecu, you need to use the r33 yoke (it is the begining of the driveshaft that connects into the tranny), the transmission mounts must to be changed (the r33 tranny seats a little farther than the r32, you'll need to custom your cluster if you are going to use the r33 tranny (r33 reads the speed digitally and r32 use a cable from tranny to the back of your cluster.).
If you don't mind for timing and you want the r33 front end too it's going to take really a lot of work!(I'm doing right now this conversion, r32 with r33 front end and complete front end wiring harness with the rb25 motor....lol it is really been a lot of things to do.)
gl with your swap.