mate in my view go a L20b there cheap as chips n there not hard to get some power out of.a set of webbers n a cam will set u flying.. there a cheap and fairly easy engine 2 put in.. the onlyt thing is they wel effect performace ( handling) a skwidge and its said that they r a bit tall.... if u go a ca u will have a weapon.. but its ve3ry had to put them in...... 13b's belong in mAZDAS n it would be hard with rego etc . have fun n goodluck