Nice to see another X5M owner posting here.....its quite a rare thing!
Pictures of your new X5M please
Re the exhaust, 'Sport+' mode results in the existing exhaust valves being open all the time, however you may not want to drive in 'Sport+' all the time, so you can either purchase a valve controller unit (which means you can have the valves open in any driving mode you choose) or you could unplug the valve controllers (by the exhaust) once open, to stay open all the time which ever driving mode you are in.
Unfortunately BMW do not offer a M Performance exhaust similar to what you can get for the M2/3/4, so if you are thinking of changing exhaust, you'll need to go with one of the big providers like Akrapovic, Fi or I think Hamman do a full exhaust aswell but they are £££'s.
You've got resonator delete option for a bit more vocal sound but if its pops and crackles, electronic wizardry seems to be the way forward with options like BootMod3 where you can personalise lots of setting to your own requirements.
I hope that helps
A couple of pictures of my X5M which is just about to go up for sale in case anybody maybe interested......

- d side.jpg (195.98 KiB) Viewed 3457 times

- exhaust 2.jpg (162.77 KiB) Viewed 3457 times