i'm not picking on you mate but have you tried searching? There is a tonne of info on this sites wiki about this conversion as well as CA, you need to know wether you want to SR20DET or SR20DE, DET is not registerable in a 1200, CA18det is.
If your really serious about it do some research, some shops will charge you between 10 and 15, others between 12 and 18thou. Be prepared to pay for SR!

are you saying an sr20de into a 1200 coupe is noy registrable?

nah he said det isnt

Here in NSW the rough measurement is 3 times the register weight for normally aspirated cars & 2&1/2 times the weight for turbo/superchargers. So a 740 kilo 1200 sedan is allowed 2220 cc's N/A or 1850 cc's turbo. 120Y's are heavier, so can use larger engines,1000's & 1200 utes are lighter, so are only allowed smaller ones. There are always exceptions to every rule, of course. So if you want an SR20 in your 1200, it will probably have to be a N/A one. 150 HP in a 700-800 kilo car will still be fun.
Kits to fit the SR20 into a 1200 are available, Maddat in SA springs to mind, but fitting an SR20 prettymuch means you can keep the body shell & replace everything else.You'll need to fit a bigger transmission tunnel if it's not an auto, bigger brakes & a bigger diff. As for how much, it depends on what youcan do for yourself. Can you do all the assembly yourself, or do you need to pay somebody else to do it for you. Labour costs can be half of total costs if you can't do it for yourself. I'd suggest you talk to Maddat, call Stewart Wilkins Rallying at Windsor & pick their brains about costs & find your local RTA inspector & talk to him, too. Is your's the 1200 ute I saw at SWR a little while ago with the broken inlet manifold?