Bad differential

[murph914]

Hi all. 1st post since I got my 6!

So I just bought a 2014 650i in September Brilliant Silver with M package, 20" wheels, and most of the options except heated steering wheel

All was swell until I heard what felt like a wheel bearing but wasnt turned out to be a diff. BMW Gallery Norwood in MA is telling me a 7+ day wait for the new part.

Here's my question, while they are in there does it make sense to have them replace the springs with Dinan sport springs? I am sure I could get some help from them on the labor especially if getting at the rear diff means dropping the suspension.

Thanks,
Murph