First 3D printer, open source me!

Hey all,

First post here. I'm a mechanical engineer with an interest in industrial design and I have some ideas locked away in my head / on cad I would like to prototype. I considered paying someone to 3D print my stuff but I imagine buying a 3d printer would pay for its self pretty quick as most people charge .25c a cube cm as opposed to filament costing about .03c cube cm. Then of course theres the awesome factor of having a 3D printer and the ability to prototype instantly at your fingertips.

I originally started off looking at makerbots and quickly realized I don't want to pay $2000+. I saw a ctc on ebay (chineese knock off makerbot) after postage that would still cost me $800+. Then I came across makibot? and other kickstarter campaigns and got really exited. large build volume, nice looking acrylic construction, heated bed for $300. Then I got really disappointed because it was too good to be true and the wait time on one appears to be about 1 year. Finally I stumbled across the open source DIY kits such as the prusa and mini kossel.

I'm after a fairly large build volume 200*200*200 would be nice, heated bed, it be visually appealing and cost around $500AUD delivered. (I don't want much I know)
I am looking at the "reprap g3d from "gadgets 3d"
http://gadgets3d.com/index.php?route...&product_id=93.

and also the Prusa kit form 3d stuff maker
http://www.3dstuffmaker.com/semi-bui...semi-built-kit


They both come as a kit and appears to have everything apart from a heated bed, although the power supply is included for $570 delivered for the reprap g3d and $500 for the prusa from 3d stuff maker. This is the best I have found so far. in terms of looks the reprap 3gd wins, it also appears to have a good online support with detailed manuals. Unfortunately it is out of stock at the moment. :( Does anyone know if I can add a heated bed after and how easy it would be? On a separate power supply perhaps?

The Prusa from 3d stuff maker comes with a 0.7mm nozzle and runs off 3mm filament I believe. Im after a fine print so I would want a 0.4mm nozzle to get fine layers at 0.1mm thickness?
Finally the reprap 3gd runs off auduino and the prusa stuff maker just runs off a custom pcb by the looks of it.

I think the reprap g3d lwould over all be the best, Is there any other kits you would recommend?
I can solder and putting the thing together doesn't bother me and is probably my only option to cheaply get something to Australia.

Also final question, I cant code, my understanding is i download code for the aduino specific for the prusa then manually go through and change the parameters. is it really that difficult?
Many thanks.