This morning I drove 1 hour to a BMW specialist. A guy who owns a shop that is focussed mainly on BMW performance upgrades. Most of his customers drive track on a competitive level. He has done hundreds of E46's.
I explained to him my problem, that after replacing the steering rack 3 years ago, all the troubles began. Regardless what alignment specs I used, something was off. I thought it was just bad specs, but I'm starting to think it's something else now. He said he had a similar problem with his wife's E46. Complete suspension overhaul, and the steering still felt really weird. He replaced the steering rack ***61664; problem solved.
I told him what alignment specs I used the last alignment, and when he test drove my car, he said that the car felt waaay to twitchy and unstable for those specific specs. It was driveable, but it didn't drive like and E46 is supposed to drive. He also suggested I swapped out the steering rack. I told him mine was only 3 years old, but when I said that it started afterwards, he definitely thought that is the problem. But it's a new one, I said. He replied that it was a rebuilt one, as I had to turn in my old one. And that there could be a slight chance that it was not rebuilt correctly, maybe because it was a Monday morning and the tech was still drunk or something, and that the teeth from the middle position had too much wear but that it was neglected. Just an example of what could be.
I find this hard to believe, as there are (almost) no steering rack issues known for the E46, but he claimed that he had few customers who requested a new steering rack, while he test drove the car before, and found nothing odd about it. Yet he replaced the steering rack and said that it drove like a completely different (new) car. Also, his E46 track car has toe OUT in front, and 0 toe in the rear, and it drives as stable as an E46 can drive. I said that my E46 with these specs drove even worse than it does now, on which he said that this is normal. If there is a problem somewhere, and you use more toe in, you are camouflage the problem, the more toe out, the more the problem gets "exposed".
The issue I have now is: I still have a steering rack from a 330iA with 300k km lying around. Should I swap that and try it, or should I just go for a new one? Save money but having the risk of having to do it twice, or spend money and do it right?