It looks like a good one, from the photo's it has a feeling of being looked after. The interior isn't original as those seats wouldn't have been fitted to a 135 but I don't see that as a problem just an indicator that an owner has spent time and money on the car at sometime in the past.
I'm not too worried about potential hg problems - if it fails, it fails and I'd get it sorted.
Do these cars have any particular rust issues?.
Also, at what kinda mileage do the clutches need replacing?, as if a potential purchase is near to clutch failure mileage, I could use it as a bargaining tool on the price?