So in installed a chip from eBay this morning on my 1987 924S. Installation was easy, but what they fail to mention is the evil plastic cover on the back of the ECU. Remove that first (2x Phillips screws), otherwise it will carve your hand every chance it gets.
In terms of performance of the chip, it works great. I purchased this one...
Stage 3 EPROM Performance Chip For 1985-1987 Porsche 924s 944 ECU DME Race +25HP
Also available from
I find the plus +25hp claim a little far fetched, but definitely feels faster. Tried a 0-60 and came in at 7.8 seconds with a really sloppy 1st to 2nd. I had some flat spots over 3000rpm before, now with the chip they don't seem to be there. I'm pretty happy with the performance improvement for less than $50.