Technically those half inch offset wheels are zero offset and the standard maxx/revo wheels are negative offset, the narrow the vehicle. Ofna makes some positve offset wheel which significantly widen the car and do put stress on the axles. The "half inch offset" are fine and you shouldn't have to worry about it. Just look at all the 1/8 scale truggies, they all use either "half inch offset" wheels or extended hex hubs. Here's a pic of the standard wheels
and here's one with half inch off set
And here's a little blurb from Pro-Line about why they are called standard and half inch offsets (we can all thank Traxxas for this logic):
Terminology
· STANDARD OFFSET
Refers to standard MAXX® offset wheels ( stock wheels )
· 1/2" OFFSET
1/2" offset will increase track width by 1/2" per side over the stock wheel.