When you high discharging your lipos I mean 40A discharge, always? or before a race? or sometimes.... I have understood is to reduce IR, can it be done hours before a race or it has to be inmediatly before to cylce...?

from my knowledge its to get heat in the battery which in turn reduces IR.

basically you have to time it to be beneficial.
know how long it take to discharge at 40 amp and charge at 20 amps( or more)
and time it right before your heat/main. (i don't do this cause i cant afford new lipos every 3 to 6 months).

heat in lipo is what reduces the ir but most have rules where you cant heat the outside so u have to do it internally.

This is done alot in one cell stock racing. High discharge creates heat in the battery which reduces IR and gives a little extra spunk up front but, as stated, if this isn't done back to back just before your next race, it's all for nothing. If the battery sits a few minutes after this disch/chg cycle before the race starts, nothing gained. I don't think this would be worth the hassle for 2S and up.

I think the whole idea of getting the battery warm is ridiculous. How long until the "if some is good, more is better!" attitude takes over and someone blows one up on accident? I remember a few years back they were checking battery temps in tech...

checking battery temps does nothing when u heat lipo internally the outside case is below what legal.

i have even heard of discharging at like at 60 or 80 amp which is insane

OH it matters Andy, it matters! Current charge/discharge rates are at or pushing 70amps plus, on 2s packs....across the country for 17.5 racing.

I'm not doing it, but I've run "pushed" packs as some call them, and yes there is a difference.

If you haven't seen it happen yet, you will. One of the tracks I race at has adopted a no-discharge, 2C charge rate max rule. Much like many things in stock racing, it's on the honor system but it's something I could see becoming a trend.

I'm still a little scared of lipo packs. I'll charge at a 2c rate on my 4s but thats it. Last thing I want to do is start a fire.

It depends which lipos are you using. You have noted what capaciy of your lipos.