Answer: The breather mod we would recommend on all wet sump engines for road, track day or club motorsport. If you are dry sumped using our own dry sump system, we would run the engine completely sealed (Except for the drysump tank) and there is no need to carry out this modification. The modification prevents a build up of oil in the cam cover breather which can be sucked into the engine intake system causing engine failure either by a hydraulic effect or detonation from the oil being in the combustion chamber. The other problem is simply the reduction of oil in the sump. (Our Drysump systems has very large scavenges which are able to produce a vacuum we only recommended this modification for our own systems if you carry out this modification on system with to smaller scavenge pumps you could pressure engine causing serious damage).
The only other modification we do to the breather system is on the works cars. We used to insert tubes into the cylinder head and do a completely different modification to the cam cover. But this is not a modification we would suggest for club level due to the fact the modification costs in the region of £300 and is not possible for the individual to carry out without full machine shop facilities.

Links: Set Up Information

Answer: Yes, we would normally make the exhaust cam the same length as the inlet cam. There is no need to retain the last bearing