Don't forget to soak all or your suspension tubes, inside and out, with a high quality anti corrosion liquid. They rust and parts are no longer available. Lanoguard is the latest fad. Waxoyl is pretty rubbish to be honest.
I've had same issue. Fiat can't source them.
They're M12, with 33mm eccentric washers, around 115mm long.
BMW part no 33326764292 fits & is available. The bolt is a bit longer (125mm) but plenty of thread so you can shorten if necessary. I'd recommend getting genuine BMW part as the cheaper Chinese ones I ordered 1st are rubbish quality & the removable washer doesn't key properly on the bolt.
I used zinc plated high 10.9 spec tensile bolts with a half nut to lock in place and a thread cover cap to keep rust at bay for removal. I use the same spec for the bottom arm ball joint pinch bolt. Both are well coated end to end with a high spec anti seize.