Nice choice. 
You'll soon be known as Tunnie Two Coupe's then.

Sadly the 435i will need to make way for the M60
Ah, my mistake, I thought you were keeping the 435i and getting rid of the other one, but that makes sense now.

I like the F32/F36, it’s a nice car to drive.

Mostly ticked for the bike carrying option, we have a roof rack for the Zafira, but lifting bikes up there is a pain.
Towbar mounted racks look much easier and also don't have to keep a roof rack on there all the time. Fitting roof rack takes time, hammers mpg when not in use etc.
Bonus is I could rent a trailer locally for camping trips and take a load more stuff!
I use Thule Wing Bars for the Roof Box and Thule 598 quick release cycle carriers for the bikes. Once you’ve set the bars up, fitted the fitting kit to the threaded holes under the roof flaps, you’re good to go. Probably takes around ten minutes for the bars and bike carriers once you get used to it, and then the bikes, which isn’t too bad as the 4 Series is low. The Thule 598’s just slide into the T Tracks in the bars and clamp down wherever you want them.

I never really took to my towbar cycle carrier as I needed to fit my trailer board as the tail lights were partially obscured. As you say though, the towbar will always come in handy.
Pros and Cons of towbar mounting :
Pros : Less height to lift them. No height restrictions when parking. No wind whistle. Quick to remove when not required.
Cons : Awkward to fit some bikes. Men’s bikes are easy but women’s/Childrens bikes sit at an awkward angle due to the down tube, thus obscuring tail lights which then necessitates a trailer board, which adds time. They also need strapping on. The bikes will bounce with road imperfections and road humps.
Pros and Cons of Roof Mounting :
Pros : More secure during transit. You can (allegedly) travel at high speed when they’re on the roof.

Quick and easy to fit in the racks if you’re able bodied and takes seconds to strap the wheels. You can stagger/alternate bike directions to get more bikes on the roof bars.
Cons : Obvious height restrictions when parking. Takes a few more minutes to fit the roof bars. Square roof bars can whistle, whereas Aero Bars are quieter. Some may struggle with the extra height required to lift the bikes. Takes a bit longer to remove when not in use.