I picked up a mint Carrera Luna 24 for my daughter a couple of weeks back. I’m looking to get some weight off it (was 29.5 lb in original spec).
Have already swapped the tyres to some Schwalbe Table Top folders from Rutland cycling (£5.99 each off ebay) which dropped 350g of rotating weight, bar and stem have been swapped, fitted straight bars for better riding position and small weight loss (although standard items were surprisingly light).
I think the remaining obvious things to target are forks & wheels, forks being the easiest. As recommended, I’m on the lookout for some old SIDs or similar. The Luna has disc brakes so that makes life a little easier as a 26″ fork is a straight fit, the standard issue forks have a very similar axle to crown measurement as a 26″ fork with around 80mm of travel so geometry should be fine…