you sir need to swap to the old style intake manifold from the m50/s50 (e36 325i, 95 m3) as it is has much larger runners and will probably give you 10hp without any kind of tune or anything else. you can get this used from many many people on bimmerforums.com or even from a junkyard.

if youre looking for a simple drop in chip you'll need to convert your motor and ecu from OBD II to OBD I stuff from the earlier 24v motors. your obd II system would have to be reflashed (still easily done by turner or any of the others). lots of people convert to OBD I as it is simpler and considered better.

your s50b32 is a beast waiting to come out. just spend time researching on bfc.com, theres more info to be had there than you can handle. if you need any bmw help hit me up its pretty much my thing