If your having trouble fitting the SP speedo, have a look at Jimmys reports in the News section, there are pics of Ellis Staffords Pred with the speedo on its side behind lo pro servo (solder leads facing upwards), neat way of doing it.
Here is a link to the pic:
http://www.oople.com/forums/showthread.php?t=47900
Once ran on the 13.5 I'm going to be getting a 10.5 for mod racing as the cars so light/free drive train it doesnt need a big motor. 10.5 with a bit of boost will be nice I reckon.