I use an M3 for my center channel and in many respects I found that it actually has a little better wide angle dispersion than the VP150 and the voices sound a little more natural. That is why my VP150 is sitting in a box in my basement.
For that reason, I would recommend that depending on the positioning of it related to your monitor and L/R speakers, you leave it upright and tilt it(if necessary) toward the listening position.
I’ve been looking at using mine for a trade-up. Looks like it will give me 40% off any non-factory outlet items I buy up to $867.00 and it looks like the 5% HT discount still applies.
I’m already in the market for 2 surround back speakers and possibly a couple of ceiling brackets and possibly something to relieve the M22s from the mundane duty as wide speakers.