i must admit i don't know much about the speed passion products, hopefully someone who has used them can advise on the settings to use for the speedo. I would leave it at the default profile for the time being unless the manual gives different profiles for touring car and offroad etc.
You should be able to race with your system fine. You may find your car is a bit slower than the others as you are only running a 13.5 (depending if your club runs open modified or limits everyone to 13.5). But don;t upgrade the motor until you can happily race a 5 minute run with out crashing. If you put a faster motor in to try and keep up you will only crash more as the car will be more difficult to control.
If you plan to race in the local regional championships then you may want to check your motor is BRCA legal. Look at the electric list on the BRCA website.
In terms of the car set up for your D4, have a look at the link below which features set ups from all the team drivers. THe Batley set up from Adam will probably be a good starting point for you.
http://www.hbeurope.com/setups.php?partNo=61410&lang=en