what are the differences in a d15b2 and the d16__motors? cause i have a d15b2 that is converted to si(mpfi) but i dont know what is interchangeable or if the d15 is even worth keeping.and can i do a mini me out of a d15b2. oh and i bought and installed a zc cam or so that is what i was told. can you even get a zc cam for a d15?