i did this, and find it not to be overly compicated - the mounting points for the short (facelifted) Valeo units are the same as the mounting points for the long (pre-facelifted projectors) Valeo units. On my 4.8iS there was an air channel that was getting in the way, but if you push it hard enough, the plastic will "give" and the longer housing sits just fine.

The main change over was in the connector and the pins - the original connectors was to be cut off and the new connector with new pins was to be crimped in. I even heard that some folks made a little wire adapter, that used the vehicle's original connector and adapted to the new projector recepticle...

not that hard... part numbers are on this forum, in other threads on this subject.

what smaller projectors are you referencing?