Awesome update and damn that's the nicest OE ash tray I've ever seen on an E46!

To your notes:

Dampers - if you want to really maintain/enhance that smoothness, then go with the Koni FSD/Special Active over the Yellows. It's amazing how much they soak up bumps and are no slouch in the handling department. Can't beat them for a DD.
https://www.tirerack.com/suspension/tests/koni_fsd.jsp

Sway bars - a simple OEM upgrade is the Z4M front bar (27mm compared to the 23.5mm ZHP bar). It also has the same angle on the mounting points, whereas the M3 bar (26mm coupe, 27mm vert) fits, but has straight tabs that put the non-m end links to their max twist, sometimes causing bind. I have the Z4M front and a non-m vert/xi rear bar (20.5mm vs 18.5mm ZHP) and it works out well. I think I have a few sets of adjustable sways in the garage too that I haven't tried...

PS4S - hell yes, amazing tire. I've found that they're really sensitive to pressures - 32psi cold is perfect for me. Right now I have mine at 33psi cold and they get up to 37psi while driving, which is enough to make them slightly harsh and reduce the confident grip feeling.

Adaptive headlights - my favorite aspect of our coupie bois. You'll be giggling the first time you cruise down some winding rural roads at night!

Kamikaze roundel - lol