Theres heaps of different things to look out for. The U12 is more squarish and the U13 is more round. U12 (if its stock) will have either the CA20E Engine or KA24E whereas the Bluebird (if its stock) will have the KA24DE or SR20. Both FWD excepting the SR powered Bluebird in which case it will be AWD.
Also U12 Pintara and UA Corsair (which is what you have) have some subtle differences in body kit and so on.
Do a search on the top right and all will be revealed stooge.... oh and welcome as well.
P.S
Search in the Wiki articles and you will see more U12/UA differences.