As mentioned, the shims go onto the outside of the posts which will move the servo towards the outside of the car, away from the top deck.
I would also advise using the rubber grommets that come with the servo's (it it came with some), use those as well as the posts that come with the T2's never seem to line up as well as they should, they always seem just a bit too far apart.
Xray T4'16, T4'14 (Wet Car)
Xray X12 2016
wlrc.co.uk (West London Racing Centre)