About the durability - i have done around 1000km on M500 with M600 controller (1.1kW peak) and everything was perfectly fine till i crashed last month and then damaged nylon gear and mid-gear with clutch (and got spare set from Czech).
In my opinion the 'new m500 gear' is fairy tale, because it...
You just need new nylon gear and new stator, to match the teeths.
I just checked mine gear (M500 from 2021 and it have 32 teeths).
Personaly its first i heard there was 'later' version of M500 with same gear as for M600.
M600 stator will not fit. Its too long. You need to look for 'new M500'...
Interesting thing, the 14.6 firmare on L1 seems to going to 6.5A, so higher than 46.9.
Could anyone compare the 14.6 vs 46.9 and confirm findings? It seems the new 46.9 firmware have weak L1 and standard L5.
I tested today the 46.9.
L1 going to ~4.6A
L5 going to ~19.6A
Battery drain on L5 seems to be similar to 14.6 and lower than 46.7
Below tests done on same exact same distance, similar weather, similar outside temperature, always from battery 100% charged.
*note my engine is M500 with...
KK blackbox from @Dado is no brainer. I am using it and no better choice.
You may also buy the BESST interface, i have this one too, but if you want something for easy and 'daily' - pick the above blackbox.