Hi all new to octavias in fact not got one yet still looking for right specced f/l vrs but anyhow coming from mk4 golfs I know really 10s were really limit on rear is this the same for a mk2 octavia or anyone squeezed 11s on rear, cheers

Why would you want to fit a wheel that wide?  On an 18x11 wheel the narrowest recommended tyre is 275!  Very doubtful that will fit under the wheel arch.

I don't really but the wheels im looking at are staggered, id rather have 4 fronts at 8.5" but just asking the question

10's have been done so I can't see why 11's wouldn't go with the right offset. The octavia isn't as generous as it's vag brothers when it comes to arch room thou.

I run 8.5x18 et25 alround, the fronts are at the limit but the rears I think I'd get away with et20.

Try http://willtheyfit.com