And to explain "why" LSA is important (using that awesome graphic) you have to remember in a boosted environment you are actually cramming your combustion chamber full of air under pressure. If you have overlap (that small section where the two lobes cross over in the graphic, this is actually when both the intake valve and exhaust valve are open at the same time), what you are effectively doing is cramming all that boost right out your exhaust. You don't want overlap in a boosted environment as it is a giant boost leak straight out your combustion chamber into the exhaust right when you are trying to fill that chamber with fresh air.
You want that overlap in a NA environment because you are in a negative pressure state and it creates a scavenging effect which effectively sucks more air into the combustion chamber. At that point the exhaust pulse has gone down the runner of the exhaust manifold or header, and has left a negative pressure zone behind it. That negative pressure zone is under vacuum and effectively sucks air in from the intake manifold during overlap. This is also what gives that lope-y cam sound we are familiar with.
LSA is a massive influence on all engines, it just works differently (and oppositely) when you are in a N/A vs. Boosted environment.
I'm confident you know this, but as a point of clarification overlap does have its place in forced-induction engines. It aids low end responsiveness, the portion of the rev range that the manufacturers are most concerned about. Car buyers don't want turbo lag and will pass on an otherwise fuel efficient engine if its performance feels sluggish. That's why VW/Audi introduced their Variable Valve Timing system to the turbocharged 5v engines in the 1990s. Here is an excerpt from their Self Study Guide explaining the benefits of variable valve timings:
We at FrankenTurbo have been working on the VW/Audi engines for some time now, so naturally we got "Cam Cards" for those engines as well. With that information we can illustrate how that platform's VVT system functions:
As dyezak pointed out, the VANOS system makes that old VW variable valve timing look pretty obsolete: it not only has control of BOTH cams, it also can specify the exact amount of separation on the fly. Here is a graph of the N54's VANOS system with examples of possible "Torque" and "Power" positions.
Lastly, since I have it, here are the VAG cam profiles compared to their BMW counterparts.
When you look at the N54's camshafts versus others, they stack up pretty well. They have more duration and lift. The only profiles in this graph that holds up against the N54 is for an upgraded CatCam intake (in pink) and the European-spec RS4 exhaust.
Thx