There are some real experts on here that may offer additional advice, but considering your bike is close to stock, here are my comments:
1) Stock A/C, perfectly adequate and little if any to be gained from changing it.
2) MR103, can't say - I did the TTS100 and very happy with the results. Again, most "bolt-in" cam changes will give only modest improvements in torque and HP. Real gains will come from cams along with head work and compression adjustments. That type of work get's expensive and voids most warranties. TTS100 was a very noticeable seat of the pants performance gain. Hope you get similar results with the MR103.
3) Great that you have replaced your lifters with non-HD lifters. They are a problem for most 110's at some point. Mine took out the entire engine at 42K miles. Most riders have failures at or before that point with the 110 stock HD lifters. There are tons of posts about this issue.
4) Probably will be told that these head pipes are sacrificing low end power. If it's only noticeable on a dyno, then probably not worth worrying about.
5) This too (like #4) will get you lots of comments that you are losing power. I had purchased RCX 4.5's for my bike before researching slip-ons. I liked the look and loved the sound. I do think I felt a loss of low end power when I installed them. Anyway, when I changed my head pipe, I liked the sound of the RCX 4.5's even more - but they did get pretty loud (not a bad things as far as I'm concerned). When I received my new motor (after the lifters failed), I installed the TTS100 cam and planned to have the bike tuned by Doc (in FL). He'd already told me that the RCX 4.5's should go. I swapped them for CVO cans with Fulsac 2.0 cores.
6) PV - probably very adequate for your current build, but may be limiting if you do more extensive work down the road.