I bought a standard 25Cal Condor Series E on the recent sales, and added an AirForce FATS adapter for a moderator. The trigger on mine is pretty darn good, but I can see where it could be better. I dont plan to touch it however, this is a hunter for me so I dont want a super light trigger. Accuracy with 34g FX pellets has been impressive so far, but I havent done extensive testing yet, and no slugs at this point. A set of BKL rings is a must in my opinion, as they are some of the only rings that clamp a dovetail evenly. If you use a regular adapter or rings you will have a setup that is either canted or off-center. The AirForce rail is a different dimension than your standard European 11mm, I think its probably a 3/8".
I dont think you will need a lot of upgrades or extra maintenance on a Condor, thats kind of the reason lots of people are drawn to them. I do plan to add a Hubben reg and 300Bar bottle to mine at some point. I wanted a Condor SS but the 24" barrel version made more sense for my planned use, as I can still get max speeds with a regulator. I plan to run 34g pellets and Nielsen 34.9g slugs so the reg wont really limit me at all. I also removed their new tactical forend, I found it to be bulky and a little awkward. I thought I was buying a Series D, or at least a Series E with the old style forend. But what I got was the newest production.