Hi all - it's been a while, but I've got an interesting issue.

2006 3.0 6MT, 141k on the clock. Current symptoms: slight vibration at speed and caster is out of spec.

Fall 2015, I refreshed the front end myself (control arms, tie rods inner and outer, and ball joints), and had it aligned locally. I always thought the wheel was a bit off center, but it tracked true, and the refreshed front components made a world of difference - tie rod ends and control arm bushings were shot.

Jan 2017, I had the BMW dealer near here refresh the rear end components (that I had purchased back in fall 2015, but put off doing because of the PITA nature of the front end). Labor was actually reasonable, and I had them align it after. Result was Alignment 1 image attached - they noted the front strut was likely slightly bent and recommended replacement. It still drove wonderfully, minus the damping, with now fresh (less than 5k on front) bushings and joints, for about 3 weeks - then I started to notice a vibration creep in. Switch to summer tires did not cure or exacerbate.

April, 2017 - I went ahead and ordered Bilstein B4 dampers and mounts (every component but the springs on the struts) and changed out the extremely worn dampers. Fresh dampers, as usual, are a revelation. But the vibration remained. I went ahead and took it back to BMW for another alignment. Result of second alignment is attached as Alignment 2.

New strut fixed camber, but the caster is still out of spec evenly on both sides, and the slight vibration remains. In gear, clutch in still in gear, in neutral, under acceleration, coasting, braking, it doesn't make change the vibration. No associated noise. I don't feel anything at exactly one speed - a random 64mph, but anything past 60 and you notice it.

Thoughts? I am going to check wheel balance this week, but both winters (on wheels/tires with less than 4k on them) and summers (9" square style 63s, in ok shape) exhibit same vibration, so I'm assuming that's not the cause.

TL;DR - all new suspension components (everything in suspension but springs) within 5k miles, caster is out of spec and slight vibration at speed, stumped.

Attached Images