In Japan the RSX S12 Gazelle also came out with an FJ20ET, R200 Longnose IRS LSD Rear end and a mean ass looking bonnet scoop. They were a wicked car, and if I ever bought another Gazelle It would be an RSX.
This is my old S12:
http://datsun1200.com/modules/newbb/viewtopic.php?post_id=225495They are not really worth much money (except the RSX), especially if its just a stocker with a CA20E. They came in two forms, the notchback & the liftback, and they came in both solid rear end with H190 diff, and R180 IRS - both are VERY hard to find LSD's for. I locked my H190 :P
CA18DET will bolt straight in with stocko gearbox, as will SR20DET (with SR gearbox) and FJ20ET (with box) like mine had.
They are a pretty sick car if I do say so myself, I had alot of fun in mine, but if your only looking to trade to make money I wouldnt even bother. N14 will be way easier to sell.
Check out
www.s12silvia.com for idea on price, ive seen SR20DET equipped ones go for around 3.5k
Hope this helps.