Not even sure if this type of computer can be upgraded. There should be many other ways to get extra power out of the car and even increase fuel economy. Check out http://www.classicvolvo.com/, http://www.kgtrimning.com/, http://www.vclassics.com/contents.htm, http://www.vp-autoparts.com/, http://www.v-performance.com/about.html, http://www.vcoa.org/, http://www.volvoclub.org.uk/, or http://www.ipdusa.com/. This should give plenty of places to get the info you need to get more power. Simple things like better plugs and wires, synthetic oils, and better breathing air filters is a good start.