Re: chain touching rear tire
Yep, many like wide tires; cars, motorcycles or even trucks. At times it is performance related but many times it is just aesthetics. Sure I have wide tires on my vehicle and they were also part of package. They are wider than the non performance package but the vehicle is pushing 550HP. You can get the same package on the smaller motor but also has about 250HP less; in that case the wider tires are really pointless.
In your case, the seller probably needed to put a new tire on anyway and decided wider will help sell it and the new owner can deal with it.