@Klooney
Firstly Congratulations.
The Jazz is a fantastic product, I absolutely love it. I would have bought one if I had enough funds & parking space in the garage.
Regarding you're queries,
Majority of cars especially petrol ones don't come with sump guard.
Regarding Anti Rust coating, you can go for it if you use car in water logged areas.
Sales of Jazz has been down, it's got to do with more of production adjustment. And the numbers are not actual sales but shipments to various dealers in India.
Still the car is in good demand, and it is the best car in that segment now.
Looks wise it is a very stylish car, which most of its rivals also are.
Performance is also very good, petrol has strong mid & high range while diesel has superb drivability.
Ride is pliant and better then most other Honda's, and handling is good. So its good here also.
Then there are these USPs of Jazz, Space is excellent and the seats also are very good & comfortable more so the Magic Seats. Practicality is class leading, so all in all a fantastic car to have. Although most have complained about quality of Jazz, it is at par with Polo & i20. Fit & Finish is good throughout.
So enjoy you're new car mate. No second thoughts.