Sportlines are only really a trim difference, so everything that Gibby has said will apply to it. It should have the original recaro seats in it, and these do tend to wear better than standard seats. Check the electric roof is working fine, and make sure they give you the tonneau cover for when it is down. These have an extra flap on them, to disable the roof motor when the cover is on.
The matey matey guide is a good one, and should give you a good idea what to look for. If you want to start individualising a cab, then the sportline is a good platform to start from. There are only around 450 out there, so it isnt too common either.