Presumably you have gone back to the selling dealer as they have primary responsability with respect to your statutory warranty under ACL.
No doubt the 20" rims, low profile tyres and stiffened up MRC shocks in Sports mode combine to make the ride less than compliant but the car shouldn't rattle, squeek or grind. Having such noises would be a concern to me. Does it make such noise in touring mode?
Sadly, it could simply be an example of poor quality build or possibly an MRC shock issue or any one of the issues outlined in the threads on the VF forum. 1st thing I'd do is try some silicon under the exterior windscreen top seal and on the door seals, maybe wrap the striker in a turn or two of electricians tape,
read this thread for details. Then go for a drive and see what noises are made, if any, hopefully it will be quiet and that should be the end of it.
But whatever you do don't accept such a poor answer from the dealer. They must sort out your concerns.
Do note that if you didn't take a MSE for a test drive prior to purchase, they can't state it's normal unless they can provide a representative example to demonsrate the case. But if you took out a SSV Redline as a close approximation to the MSE prior to purchase, and it didn't make such noises, then the the only conclusion can be the supplied MSE is not representative of the quality of the vehcile you test drove and as such you'd be in your right to return it and get a full refund under ACL which should get them focusing on solving your concerns
It maybe worth checking if any local dealer has a motorsport 'demonstrator' available. Consider taking that for a test drive as a comparison to your example. Record the drive on your phone and then do the same drive on the same road in your MSE again recording the event. That should give you good back to back comparison and evidence. If there is a big difference in noise, the selling dealer can't claim they are all like that. If that dealer with the MSE demonstrator is not accomodating call HCC and outline your problems.