I agree, very informative thread indeed!
I can't speak to the other can's on your list, but in regards to these, they are a flat profile, basically a studio reference can, and if thats what your looking for, by all means, enjoy those can's. I have the LP2's, which are more of a bass heavy can, which makes them more fun then reference IMO. Having said that, I didn't feel that these can's were very punchy, they have some good low end bass though. But the M-100's are known to be flat in their profile, so don't expect real low end bass, and don't expect the bass to be very punchy.
Well, then your most certainly going to be looking at the new can's I just got, the Drop Ultrasone Signature X's. These can's not only have deep level's of bass, but these can's slam hard, especially with EQ increases! So if your looking for bass that slams your skull when the volume is cranked up, and some EQ boost added, these are the can's for you. Also, despite the can's being closed back, they actually have a surprising amount of separation, and some decent soundstage as well.
Actually, you have decent setup for can's that are easy to drive. Your Topping L-30 produces 2.3-watts per channel into 32-OHMS. If you bought the Ultrasone Signature X's that I have, and you throw your L-30 into HIGH gain, you should be able to get these can's to a very loud volume, when you have moved the volume pot to 60%. I personally have the S.M.S.L SP200 AMP, which produces 3-watts per channel into 32-OHMS, and I am able to get my can's to a very loud volume in HIGH-gain when I put the volume to 50%.
And yes, I modified it with a gold aluminum volume knob.
And I am using the matching S.M.S.L M200 DAC for my stack, works excellent!
And this is the hardware EQ unit that I use, a Vintage Realistic 12-band EQ box!
I got 22-gauge Monoprice cables linking the chain, so as not to lose sound dynamics from low quality tiny gauge cables. I got a fiber optic cable sending the source signal to the DAC. And the coiled cable that came with my Ultrasone can's, is plenty thick enough in gauge to not harm dynamics, so I just stuck with that. When I used to use my JVC SZ can's, and my V-Moda can's, I had to use a higher quality cable with them, because they came with garbage cables out the box. But not so with Ultrasone. I guess its like the expression, you really do get what you pay for.
In my experience, sometimes its a good idea to raise your budget, in order to get the quality you deserve. I hope this information helps, good luck!