A few months ago I put together a mod list for the G900/G903 which included a 2200 mAh battery I found on Aliexpress (although it came with a sticker that said 2300 mAh). I charged the battery to full on September 12th and took a screenshot of the battery life as measured by G Hub at the end of every week. There was 4% battery remaining on Nov 5th. I used the G903 with 1000 Hz polling rate and RGB on. Certainly not the most scientific testing but this battery seems like a good replacement for the original battery.
After playing around with a Model O Wireless and their ceramic G-Floats, I decided to give my G900/G903 the same kind of treatment. I’ve read conflicting information as to whether the Lexip ceramic feet work on the G903 or not but am happy to report that it does work on both the G900 and G903. The only issue I had was trying to position the Lexip feet in a way that keeps the mice perfectly level so it doesn’t wobble when clicking (apparently my mouse pad or desk isn’t perfectly flat). I ended up removing and repositioning the ceramic feet multiple times to get it right. At the time of this writing the cheapest place to buy Lexip ceramic feet is BestBuy (currently $9.99 USD).