So I'm a mini noob and my fiance has a 16 mini base model. She wants to put an exhaust on it but all the after market stuff is for center exit when hers comes out the left side of the rear bumper? Looking for any advice or if I should just do something custom?

 

Ecstuning sells a remus axle back for the base. https://www.ecstuning.com/b-remus-parts/remus-axle-back-sport-exhaust-with-102mm-angled-chrome-tip/754014-space-0500kt/
I'm not sure if there are others out there as I have a S and above was a quick search.