https://www.realoem.com/bmw/enUS/sho...diagId=33_1416
$750 on ECS Tuning.
By the time they do bolts and their parts markup and such $900 is probably not far off. Looks like a new upright comes with new bushings so that's good at least
Looking at the upright, I bet the bushing sleeve is seized to the bolt. It's actually a ball joint rather than a flexy rubber bushing you could potentiall yget out with the hot wrench, with a big thick steel insert the bolt goes through. That's a bastard to get apart, but they might be able to press that lower bushing out and replace it with a new bush rather than trying any harder to extract the bolt itself. Try asking them if they can do it. Should be less than $100 in parts.