Good luck - I am sure that if it is not ok, then you at least have better come back against a Mazda dealer than another non-franchise garage?
I am sure that you will not regret it! I pick up my new ND on Thursday too - must be “New ND” day!!! (or new to us…)
Hope you buy the car, you will not be disappointed. I bought my 30 AE RF after seeing it in the showroom with the full body kit in Nov 19. The smiles per mile are enormous, although that also applied to the rf i had before the 30AE. i will rely on the paint and corrosion warranty to expire before adding any additional underseal. With the lockdown the car hardly leaves the garage atm. Good luck.
I spoke to the Mazda dealer yesterday regarding adding underseal to my new car. They stated (but not in writing), that adding waxoyl or similar would not affect the warranty as long as it did not interfere with the operation of any parts. They did say that it is checked very year for corrosion and the rust warranty was quite long…
However I do not trust them! So I will get the car on wheel ramps and jet wash the underside regularly.
I’m leaning towards dinitrol over waxoyl atm, especially as I know someone locally who has a business restoring old cars, including mx’s, so he knows where they’re vulnerable.
I’m not intending to do anything apart from maybe jet wash the underside until the summer, when everything can dry out properly over a few days/a week or so before the application of anything.
Early days, plus it may be rubbish and I come back without it. It wouldn’t be the first time a MD car turns out utterly not as described.
Not long to wait now. I think when you buy a car like this you sometimes start to second guess yourself and question if you’re doing the right thing, I know I did .It’s not a square box family run about , everyone can have one of those . What it is is a car you get in and the whole day seems a bit more fun , you will go for a drive just to go for a drive and feel like you did when you first had the freedom to drive and it wasn’t just a mundane thing to take you from A to B.
Enjoy your car and have a great day 
You will come back with the car while singing “non, rien de rien, non, je ne regrette rien”.
Or ‘On days like these’ Matt Monro from the Italian job.
Is this car JYJ?
For perforations from the inside out though not if caused by the salt on the UK roads (specific exclusion). It really is worth ■■■■ all.
That is what I figured, which is why I will be getting some ramps and giving it a good jet wash underneath each week in winter. if there was a “reputable/professional” place around Cheshire that could do proper corrosion prevention, I would have it done. I may get a “cheap” car for next winter, but will have to see s I was trying to make more space on the drive.