this is the adapter needed to connect the wiring for a s/m5x swap in to your e30 using a e36 m50 obd1 and most e34 obd1 harness to any e30 from 87-91 325i,is,ic or 318i,is,ic. also has the extra harness for the oil level sender in the oil pan so your obc will still work. also the main power lead so your abs will still work.
$150 shipped. all label and ready to plug and play.
pm or email nitroman12@gmail.com
pic of adapter for a 87-91 325i,is, ic and 90-91 318i,is,ic (m50 swap)

pic of early 318i,325e to e34 harness (m50 swap)

pic of early 318i,325e to late e30 harness (M20/30 swap)