What you have is probably a good start. As mentioned, both torx and etorx sets are basically required to work on BMWs. An
E10 1/4 swivel is necessary for doing oil filter housing gasket and is useful in other spots. Other than that, you don't really need a ton of other specialty tools. For suspension components I think you go up to 22mm socket and combo wrenches. I don't think any larger, but if so, just buy the tool ahead of time. I highly recommended ratcheting combo wrenches, they're great! Be sure to get some quality torque wrenches, a lot of the fasteners are very specific in their requirements. You'll need a couple different sizes.
Harbor Freight has some pretty good made in China hand tool offerings, check them out when purchasing. I have some of their flex head ratchets and love them! Tekton on Amazon makes really good stuff in Taiwan, and is definitely recommended if you can plan things out and order ahead. You'll need two jack stands and maybe four at some point. Probably a creeper if you want to roll around under the car in comfort! And remember, if a tool seems expensive and unnecessary, just remember what the cost would be to have a mechanic do the job!