I think it's going to be hard to get some 1er based feedback on either of your two options as I can't say I've ever heard of either brand mentioned on these forums before. Of course someone might have tried those kits on other cars, but it's still a slim shot and won't relate directly to it's application in our car.
But yeah, it would be a good idea to decide which route you'd like to go for before asking for feedback, especially on such unusual decisions.
The only person in Australia I know of who has slammed a BMW on bags is Suj (sbce90) on his E90 320i. Not sure what brand of bags he went for though.
As for $10k on a set of springs and struts, it sounds like too much for me. There are plenty of tried and true kits out there already and most are significantly cheaper. Check out HPA. They have a huge range of top quality coilovers that can be used for racing at a cheaper price. Moton, AST, JRZ, Etc.
I have Motons on mine and I'm pretty damn happy with the performance and ride.