If your dealer tried to sell you a CT525 to take off anything other than stuff like very small bolts, he is either an idiot or lying thru his teeth.
The smallest battery impact from Snap-on that could be used on lugnuts would be a 3/8" drive CT4410 seires 14.4 volt impact. They can be used with an 18 volt battery pack but with either the 14.4 or 18 volt pack, they are good for cars and trucks up to F150 size for a pro.
If you need something with more torque, step up to the CT6850 and CT6855 series. They will handle most chores that you would need an impact for short of heavy duty trucks, Honda crank bolts and the like. They are NOT a replacement for a good air impact but will work for most things that need to be removed.
Yes, I do own several drivers and the impact in the 7.2 volt line as well as a 14.4 volt 3/8" and an older 18 volt 1/2" impact.