I really haven’t had any issues with woofer flapping on my Innovation Wood with the Universal arms. I do have it sitting on a HRS R3X isolation platform, with the LF feet factory tuned specifically for the turntable. I have a pair of REL S/510 subs so I should notice if I had an issue. My Boulder phono-stage has a 10Hz low cut filter and I don’t notice any difference with it engaged.
@dwette It’s really dependent on your floor, rack, positioning relative to speakers, and how loud you play. I’ve pushed it on all accounts, except for the fact I don’t run subs, at least.
The rumble filters built into phono stages are generally pretty mild - they can help, but not enough in some cases. The KAB filter is much steeper and works well, though perhaps not 100% sonically transparent as advertised. Isolation platforms like from HRS and CMS seem most effective in midrange - my CMS ones didn’t help solve LF issues. LF energy issues can be quite hard to deal with.
Anyways, sounds like you’ve got it all squared away for your setup, and you should benefit from and enjoy your Master upgrade all the same! Great table. I’m happy you’ll get the latest version. I’d really like that for mine, but it would probably be hard to pull off without a lot of additional funds. Clearaudio has worked in improvements over the years, which I like better than the whole Mk 1, 2, 3 [SE] type schemes.