Help me choose: Harbeth 30.2 or SHL5+ XD in a 10 x 13 feet room?

In my opinion the M30s and the SHL5s are just going to be too much speaker for that room. Even the C7s will be tricky to set up right.

The P3s will be much easier to integrate into that room. They are a bit different than the other Harbeths (sealed boxes) and can be placed closer to the walls. You will probably want one or two subs (REL T/5x would be my suggestion, one may do the trick (depending on your room) but two may be easier to integrate (eliminate nulls and peaks, DSP can be your friend). Don't underestimate the P3s; the only concern would be if you listen to music crushingly loud and like to feel your pants legs flapping from the bass. The M30s in that room would practically force you to listen near-field so reflections will be less of a concern; add a couple of subs and crank those babies 'til you reach audio nirvana!

I have the Harbeth M30.2XD’s with a REL S/510 in an 11.5x11.5 room with much treatment, and they sound fantastic. I have the Harbeths about two feet from the front wall and just over 3 feet from the side walls.

@etph thanks. I’d love to hear about the treatments that you have and how you decided on them. Did you do some measurements with REW and then decided on what to get? It will be awesome if you can post a photo of your setup. 

Thanks for asking, vzz1924. Unfortunately, I just went on vacation until the end of the month but I can send pictures when I return.  I did not use REW but trusted my ears. John Major at GIK helped me on which acoustic treatment and where and I experimented for months with speaker and listening positions. The GIK acoustic treatment made a huge difference to my small, square room. 

I'm late to the party. As someone here has suggested, I would recommend looking at Graham as an alternative to the Harbeth. Almost everyone who compared both prefer the Graham's more uncolored presentation. Most Graham owners are ex-Harbeth owners.