Well I'll start this off then by saying I think the CA would be the better option. Depending on local laws the SR20DET iss illegal to install into a road registered vehicle the size of the 1200 ute however you can use a SR20 non turbo motor. As for prices it seems to be like 10g's universally for the minimum if you're paying someone to do it. As for the RB25 twin turbo it won't fit unless you want to make your ute look like a sports sedan inside tha cabin. On second thoughts, with the ute you couldn't really do that as there isn't enough room to mount the seat back.

edit: 2 different forums within 1/2 hour and I've been jumped for the hounours of first reply.