i got the aftermarket seats, so oem seats are taking space at my apartment.

I'm thinking giving it to my friend since he likes the seat(of course better than altima seats...)
If i get proper brakets for altima, will it fit? has anyone done that?

 

you would have to completely make your own brackets and adapt the stock rails to them

 

not quite.

since altima seats are way high up there than 350z seats,
if you make rear brakets (in metal tablets to fit holes from z rail to altima rail) it should fit.

the front should fit (minor drilling require). which makes the rear sitting position of the z seats higher than factory spec, which makes sense, because 350z seats are tend to slope downwards.