@Ronin1973 Very cool rack! Lots of tasty stuff there, I like that set of filters. 14U, with 2 Intellijel rows and a TON of Quadratts, that's nice. Although I'm not sure I could hang with that crowded BL Mixer.
@ecstatic I recently installed the 1U Audio I/O on my rack, and I'll never look back. Having proper 1/4" jacks makes using the modular much less awkward. If you want to input sounds from a guitar or other instrument frequently this is a good thing to have on your rack. I also have Mutable Ears, and I also really LOVE it. The piezo output from my acoustic guitar is much lower than line level, so I need both the input +20db and the Ears +18db to bring the piezo pickup fully up to modular levels. I started out with Ears as my only input (with a mic), and yes, you can just patch that straight into Rings, or other resonators/filters, and get great sounding effects that way! The envelope follower on Ears is perfect for getting interesting expression CV out of your acoustic instruments, I highly recommend this module if you want to mic acoustic things or control your modular with sound.
Regarding VCAs:
That Intellijel QuadVCA is a good choice overall, Ronin1972 even has 2 because VCAs are so useful, but the max gain is only +6db (with the boost switch). Those Exp/Lin continuous knobs are more useful in practice than I had expected they would be, very good for fine-tuning how punchy things are.
However, also take a look at the Mutable Veils, which is a very similar quadVCA. Veils has much more gain than the QuadVCA, up to +20db in Exp mode, and so you can use Veils as a line-level input - or 4!