We have the Santa Fe with the same engine and I guess same dpf. Ours is the auto and we've had no issues in 4 years and 55,000 miles and for the last year it has been mostly driven on short trips with the occasional long run once a month and no dpf or engine management issues. The engine and auto combo is IMO the best "bit" of the car and space. There are a few stories of problems with manual Santa Fes requiring new clutches and dual mass flywheels at quite low mileages but the auto looks to be problem free (touch wood!)

Here's Kia's & year warranty exclusion statement and the dpf isn't on it but there is a reference to the owners manual for correct driving and operation etc:

www.kia.co.uk/~/media/pdf/warranty/kia%207%20year%...x

Have a test drive, compared to the Xtrail driving a Santa fe,( which i would think is similar?) i found the car awful to drive, couldn't get out of the car quick enough, bought a Mazda CX-5 instead, but not a 7 seater.

Santa Fe has had some quite different suspension settings over the years - and can be sensitive to tyre pressure settings - Sorento will be different again.

We all like different things in the way a car "drives" so it's important to try it for yourselves.