Well there's a lot of stuff going on...
There is indeed the score : The more digits below 4 the better it is.
If there are still some stuff to happen after your complete a level, like generators (for eeries, bullet bill, and so on...), clapping chucks, up and down lava,... avoid duck jumping, or facing left, because the game will have to make Mario stand, face right... while the rest is happening and will cause more lag.
Also sometimes, passing the goal bar a few frames later cause enough less lag to make it worth it but I only noticed that once and it was a slippery level with generator so not sure if it has something to do with that.
For the pipe thing, Mister explain it pretty well somewhere (probably in this thread), you'll have to search for it, but basically, iirc the lag depends on how far you're stuck into the pipe before entering it. The more pixels you are into the pipe the less lag you have.
EDIT : here it is :
[Quote=Mister]I forgot to note pipe entrance information in smw any% run's text, and I'd share it here.
When you enter a pipe from the left, you can stick yourself into the pipe before entering it. If you can get yourself stuck in the pipe by n pixels, you'll get map transition 2n frames faster than usual. Then by what pixels can you stick yourself into a pipe (or wall, etc)? Saying from the conclusion, you can get 3 pixels with speed 51 or 49, and 2 pixels with speed 37 or 33 (in water level, with item). But you must be landing on the ground 1 frame before you enter the pipe, so you end up losing your speed and the pixels by which you can stick yourself into the pipe before entering it are:
* 3 pixels with speed 51
* 2 pixels with speed 49 or 37
* 1 pixel with speed 31-33 (in water level, with item)
Here are samples with speed 51:
http://dehacked.2y.net/microstorage.php/info/1994256128/smw-pipe1.smv
http://dehacked.2y.net/microstorage.php/info/286646643/smw-pipe2.smv
The trick is used in the former but not in the latter. In pipe1, I sacrificed 1 frame to stick mario into the pipe by 3 pixels (instead of 2 pixels), and got 1 frame as a result.
This technique should be used in YI4 of any% run, but a corner-boost at the first block made us end up being stuck into the pipe by three pixels so we didn't have to do the trick. I think this is why I dropped this infomation in the text of the current any% run. :p
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