I have the retail premium version of this game, and the performance is not quite what I expect. How can I get the GOG.exe? Since I heard that it makes game run much smootherr than the retail version. Also, is it safe to do so?

You can get the gog.exe by purchasing the game from GOG.com.

It is perfectly safe to do it this way.

4 real? awwwww... So I have to pay twice the price that I already have. T___T
I think I will wait, though, for the patch ( if they intend to fix it) -___-

Well, you can always ask my good fiend Mr. G. O. Ogle. :P

goto gamecopyworld search for The Witcher 2, then select the link for Game fixes, then download the file that says 'Done by GoG'

it is virus free and is safe to do so. Even the developers say it is ok to do that and won't get you in trouble. http://www.en.thewitcher.com/community/entry/20/#comment-208033714

Yep,
I would feel safe in guaranteeing that the patch(es) will fix 99.9% of the problems over time. The trouble is waiting for the patches to mature. That also takes constructive feedback on the part of the end user as well.
I've purchased two 1.0 ATARI disc versions and three downloadable versions of TW1 just to show my support for CDPR and of course getting support out of Atari was like pulling teeth through a bucket of Molasses in January when I first tried in mid '08. Nevertheless CDPR is NOT a major publisher here in the West other than through GOG, so I would expect that they have agreements in force with Atari to help protect their IP according to US publishing and copyright law which would explain why no "standalone" patch for those not registered.
For those of us familiar with the scheme it won't seem too troubling once they get the servers up consistently and the login difficulties out of the way. I'm glad they oversold since this will only spur them to greater efforts on our behalf.

Well, I live in Thailand, and there is nobody use the GOG version of the witcher 2 around here since nobody knows anything about it- includes me. I just knew that this website exists a couple days ago. Thanks, mate.

You can pirate it ^^

And you should be warn or ban for suggesting such things to pirate a game.

I'm not going to buy twice for a game, my fps was horrible

Dude, I'm not a pirate; i'm a Witcher.

gog version has better performance? how is that possible?

No DRM. It's been reported that, depending on your system, you can see a significant increase in FPS if you have the version with no DRM.

man i knew i shouldn't buy this in retail store!!! Is there anyway to get rid of DRM in retail version though?

Well, CDPR guys admitted they won't sweat over 'obtaining' different .exe, as long as you actually has any legit TW2 copy. See eisberg77's post a little above.