I did my SR swap in my 1990 240 about 4 years ago. I got my motor set from JDM source. Not a single complaint about them and I've referred many people to them and they've all bought motors with no complaints.
I paid $2500 SHIPPED for my S13 Redtop from them with all the usual stuff (Uncut wiring harness, ECU etc.) I used my stock KA24E MAF.
I was lucky when I did my swap cause I bought the majority of the parts used off a guy who just blew his SR up. I got a FMIC with BOV and all piping, 3.75" Apexi catback, Walboro 255lph pump, silvia gauge cluster. All I sourced myself was a turbo outlet and 3" downpipe.
I rolled my car in the garage on a friday night and pushed it out sunday afternoon and started the SR. I could have done it faster but I was in no rush and would frequently leave for a couple hours then come back and work on it.
SR's don't have timing belts, they have a timing chain. I didn't change it cause it's really not a replaceable part. I also didn't change the water pump or any belts cause they were all in good shape and had been changed before.
Basically when it comes down to it, do it right. If i were to do it again I'd change the water pump and belts no matter what (just for piece of mind). Also get a walboro
(or bosch) fuel pump. It's only like $100 and it's also piece of mind that the motor is getting the correct amount of fuel. You can do a front mount intercooler @ your own will. They aren't that expensive and if you wanna play with the boost it's a must. But a side mount will do if you just want to get it running and drive it. You can pick stock SR side mounts with piping up for cheap.
Theres lots of websites out there with parts and how to guides. www.phase2motortrend.com www.pdm-racing.com www.sr20store.com www.frsport.com www.heavythrottle.com
(Really good guides and info there. Also, some good swap packages as well like all the belts and a water pump at a package deal sort of thing).
Now I know with this being revscene my entire post is going to get ripped apart and I'm going to get told how wrong I am so just PM me if you want any more info. I've done the swap myself once and helped friends many times so I know whats going on.
Hope this helps and just PM me