what length are these meant to be to fit an S1 or S2?

i bought one one ebay a while ago, seemed on the large side but the brackets lined up ok. I haven't fitted it yet as i'm waiting on a respray and was wondering if someone who has one fitted could check the size of their's for me.

Reason i ask is that i seen a mk6 one the other day which was much smaller and looked like it would have been a better fit on mine's so i'm now thinking i have a Sierra one.

Appreciate the help