Well on the power to weight ratio of the CX plus four the actual load on the engine is going to be way less so a well serviced engine probably won't have the wear issues associated with the heavier cars and might never need one fitting. Just as an aside here, I have never found modern engined cars to vaporise much oil contaminant through the rocker box breather, certainly not enough to warrant a catch can install either as a separate item or duel model in conjunction with the crankcase can.
Cooperman is spot on with his proof of just how clean the intake side will stay if you vented to atmosphere and you can achieve this using a filtered can however be aware of a potential MOT failure as this is not technically allowed but there is always the simple reversal method for that time of year. Lexus were the first to go with direct and indirect injection working together and this system certainly keeps the intake side nice and clean... as yet I haven't looked at the BMW engine to see if this is the case with it.
