From the looks of it, we can provide parts for this platform We already offer two types of manifolds for the RWD SR20:
-ProStock
bottom mount stock turbo location tubular manifold available with internal or external
wastegate.
-ProStreet
top mount manifold flanged for t3 or t4 sized turbos available with internal or external wastegate.
I will post pictures of the manifolds shortly.
custom gets my vote...easiest way to add or subtract pieces you may want. for example, you can add a high flow cat, change the # of resonators, determine muffler placement, figure out type of flanges to be used, tubing size & material etc.
here is a s13 redtop ecu pinout doc and wiring diagram pic. good luck
http://www.cm510.com/images/SR20DET%20ECU%20S.doc
http://www.cm510.com/images/sr20det_eccs.gif
a DE or DET motor that is running off the the stock ecu is very sensitive to vac leaks since its a MAF based system. this thread on the sr20forum should point you in the right direction...uses the FSM trouble shooting guide basically.
http://www.sr20forum.com/showthread.php?t=38146