I'm installing coilovers and replacing the stamped steel lower control arms on my E46 with aftermarket adjustable control arms. The stock rear camber adjustment is via an eccentric / cam bolt through the control arm. The aftermarket arms have flats and rod ends for length adjustment for camber.
Do people typically reuse the eccentric bolts or replace with a standard grade 8 bolt? Seems like belt and suspenders to have two camber adjustment methods, as well as another place for the camber to slip?
I posted this over on the E46 forum, but it didn't involve ICE, hellaflush, stance, lighting, or aggressive wheel fitment, so it was ignored. 
Seems like overkill to me but I don't have any specific experience, sorry. Unless you want all the camber.
I was taught that the ideal setup is rotated toward the inside of the car. Longer arm=less bumpsteer.
Not necessarily less bumpsteer, it depends on the car's geometry.
I'd expect the adjustable arms to be used for rough adjustments, then the stock adjusters for the fine tuning. Depends on how the new units are designed. That's how it works for our adjustable arms - the adjustment gets you within 1/4 degree, then you tweak with the factory stuff.
There's also the issue of slotted holes. If you replace the stock eccentric bolts with standard ones, they're more likely to slip in the holes, as there's nothing to keep them from sliding other than their own clamping force.
Thanks for the advice. I'll report back if we have any issues with the setup and alignment process.
For posterity -- The eccentric bolt was only eccentric at the flange and not the shank. The flange sits between two punched out guides and the holes are slotted on the oem "salad tongs" arms. The aftermarket camber arm isn't slotted, so the eccentric can be reused but doesn't do anything.
