Not quite - LFS' collision detection sucks in certain situations (lag, when a tyre comes into contact with certain corners of objects or another tyre). Other than that, what happens to the car itself when rolling etc is remarkably realistic, aside for lack of air resistance when spinning round a single axis at high speed.
From what I've seen in iRacing videos, the cars do some weird stuff while rolling etc.
The encoding of the frames itself introduces a small amount of latency (usually single digit milliseconds, so not really an issue)
The main problem however, is that packets will get lost.
Sometimes they are lost for good, causing disconnects or your car to disappear briefly.
Usually they just get resent sometime later, once it's noticed that the packet has gone missing. This means that a lot of packets, when they eventually arrive, are late. The unpredictable timing of packets' arrival means that LFS's car position prediction is getting out of date - therefore inaccurate - data. This results in cars appearing to jump around and can cause collisions when it shouldn't.
tl;dr:
Never use wireless (or to a lesser extent Ethernet over Powerline) for gaming, if at all possible. A trusty Cat5e cable is your friend.
edit: The OP's main problem is probably CPU related as mentioned before me. Any form of wireless internet will only make things worse.
It's easiest with arrow keys, but still not too difficult with WASD.
Ring finger for A, Index finger for D, Middle finger for both W and S. I can press either W or S or both at the same time without moving my middle finger off the keys - only moving it to push down in a kind of rocking motion (like a rocker switch).
It's pretty straightforward for me and this is how I've always used arrow/WASD keys. Maybe I'm just weird
A large part of the harm caused is that the mods screw with the collision detection.
As the cars used by different players are different shapes + sizes to what LFS is expecting, (when one or more person is using one or more .vob file mod) there are unwanted effects from the collision detection. The result is that the player with modified car(s) and/or other players get thrown away at high speed in a similar fashion to exceptionally bad lag hits. This can cause quite a mess.
In short, do not use modified cars online. It'll just ruin everyone's day.
The limit varies depending on the quality settings of the .wav
I can't help you anymore than that, because I haven't found out what settings yields the longest sound myself.
Regarding the skin - you've probably saved your skin as XRG_DEFAULT at some point. That skin loads whenever someone (you or anyone else) isn't using a specific skin.
PLL only tells you when a player left the track/race - not why.
If you want to know the difference between a wrong route/forced spectate and shift+S, you will need to use MSO messages afaik.
If all you need to know is that a player has entered spectate and don't care why, then just use PLL.
Normally, IRL, if the driver who won gets a time penalty given, the race results and timings are calculated based on that driver not having had the penalty, as time penalties are often challenged. The penalty is then added afterwards.
IMO this would be the best way for LFS to handle it.
However in the case of your DTM example, I'm not sure how it could be calculated to be fair (especially if the driver with the penalty wasn't the leader).
Regarding %age of laps for classification, that would probably be best handled by InSim (using the data received as each person completes a lap to keep lapcounts throughout the race) as there are so many possible variations on classification rules.
I don't know if InSim sends a packet with the "<PLAYER> did not finish" messages. If it doesn't, that would be a nice feature to have, containing info about number of laps. That wouldn't include players who entered spectate to clear the track prior to the final lap though afaik.
Check out the OutSim section near the bottom of the lfs_folder/docs/insim.txt file.
You'll need to write some software to relieve the UDP packets sent by OutSim (once you enable it in cfg.txt) and translate that into whatever commands you need to control the hardware.
There's probably more information about OutSim in LFSManual.
Locked diff - not good, but not too bad providing you don't want to go round tight corners and don't mind more wear. Typically fastest in LFS for very few laps.
Open diff - bad (the problem with the Vectra in the video a few posts back)
Viscous diff - simple, but not brilliant.
Clutch pack - the best LFS has, providing the settings are right. Getting said right settings is a pain. Commonly used as the centre diff in 4wd and drift cars.
Helical diff - (ie Quaife, the one used in the Focus RS) ideal mechanical racing diff as it gives the most torque to the wheel with the most grip. Unfortunately not (yet?) available in LFS.
Simply put, less grip == more slide, so having rear tyres that have less grip would make it easier to start a drift.
Controlling it is just a matter of throttle control - and you need less throttle with slippery tyres, so you can cope with a less powerful car - it can be quite hard to get enough torque in the XRG to overcome the grip level of the normals and keep control, so less grip on the rear would make it easier. The normals have a rather fine gap where they're slippery enough for the XRG to easily break traction, but not so soapy they're uncontrollable.
Once they get really hot it can be very hard to hold the slide, but in my experience, you have to be well over 130 degrees in road supers for that to be a problem.
In cars with enough power to easily break the traction of the tyres (unlike XRG), it's usually easier to control the slide if the tyres have more grip.
You're correct regarding the road_supers, but I did test normals as well and there was a very noticeable difference between normals and hybrids.
Just did an 8 lap run at Aston Cadet in an XFG and the drawbacks of the hybrids are much reduced, so I see where you're coming from.
Presumably due to the lower weight, power and speed of the STD cars, it's a lot harder to get heat in the tyres, so you're going to be at optimum in the hybrids much earlier than normals (if ever). Hybrids at optimal do seem to grip better than cool normals - whether that's realistic or not, I don't know, but it wouldn't surprise me.
I did find that once the hybrids got to 70-80 or so the grip was a lot lower, but I couldn't get the normals that hot, even after a lot of excessive power understeer.
Seems like the differences are quite subtle on the STD cars, as they're not very hard on the tyres. How that would compare to real-world, I have no idea.