The GM V6s are no slouch...especially the 3.8s (such as in the Buicks) have decently quick acceleration.

I thought that all of these cars were made for grandparents>>>

They appeal to older people because of their size, comfort and brand loyalty and heritage, but they're not specifically made for old people. If that were the case, Cadillac sure as heck wouldn't have had 300+ hp V8s under their hoods for the past 15 years.