Is it a 89-90 or a 91-94. What year SR are you wanting to pu in it. The wire looms are different. Easiest swaps are:
89-90 S13 = CA18DET
91-94 S13 = SR redtop or RB20DET
95-98 S14 = SR blacktop from S14 or RB25DET
Blacktop from S15 will have a different wiring architecture and require more mods to the wiring harness. I am not saying that all of these motors will not fit in the other cars listed. I am just saying that the wire harnesses will be more similar and easier to get running.
Also when buying an SR you need to decide which model to buy:
Redtop had best flowing head and is best if high HP mods are planned.
S14 Blacktop has better stock turbo and less head flow. If turbo is going to be upgraded get a redtop, if left alone get a blacktop. S15 blacktop has better turbo as well and better internals but still has lower flow head and will probably come with a 6-speed
. Sounds like a great thing, but
think about it... extra gear in same size case=weaker rears. They have reliability problems if you get above 300-350hp. Thats why many of the Japanese D1 cars have 5-speeds and/or upgraded tranny internals.
What are you building this car for? How old are you? And what kind of money do you plan to spend on the build and on maintaining the engine/car? Who will service the car? Where will you get parts? These are VERY important questions you have to answer before you can do an engine conversion. An SR may be the cool thing to own but not the best option. There are more economical optionsa as well as more powerful options!