OK, but if you had already decided to go ahead and buy a tire that is not designed for your type of vehicle, which will degrade the cornering and braking performance, and which won't be safe at speed, why did you ask?

The noise will be low compared to other LT tires, not compared to a tire like the MXV4. Anyway, do what you want, it is your mom's money after all.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue