Hi.
Dion't blame me for this question :) Is it possible to install IGO8 on a garmin device? Why I would like this you ask? I have received a garmin device (nuvi 255W) but where i live, the IGO8 maps are better than the garmin maps :( unfortunatelly. So i was wandering if it is possible to put igo8 instad of the garmin navigation. Thank you.

No way....

Garmin (TomTom too) have their own Operating System, based on Linux while iGO and its derivates (Amigo and Primo) are Windows based. Therefor a definitive NO.
When you say iGO maps are better, consider that Garmin uses Navteq maps, iGO uses Navteq too, but also TeleAtlas (+LocalProviders) maps. Either you won't get lost ;)