I have just put up a site and bought a few different domains for my main market to point to it.

EG:
bazylisk.com
bazylisk.eu
bazylisk.pl

as well as basilisk.eu and basilisk.pl

The easy way to direct all of these domains to the same site was to simply point them there via the C-Panel on my host.

My friend now tells me that I will get penalized by Google for duplicate content and that the better way to do this is via a 303 redirect.
Is this really the best way? Is Google still that fussy that they don't see I just want a simple way to use multiple domain names for identical content? A 303-redirect seems to only add a layer of complexity, hassle and slowness to the mix.

Thanks!