My thoughts...
"We breed a pet grade yorkie that is between 4.5 - 7.5 lbs"
No breeder should be striving to breed "pet grade" dogs...they should be striving to breed great examples of the breed. However,

to them for striving to breed healthy sized dogs and not tinies.
"Our puppies are available to go home at 8 wks"
8 weeks is too young to go to their new homes. The YTCA requires reputable yorkie breeders to keep puppies until they are at least 12 weeks.
Puppy Page: They have a LOT of puppies for sale from several different litters. Red flag

Reputable breeders do not have that many litters a year...they certainly don't have 4-5 litters ready to go to new homes around the same time. Several litters for sale at once means LOTS of breeding dogs.
Also, I'm sorry but these pups do not look well-bred at all...
"Each litter of puppies is registered through APRI"
I know, it is just a registry and isn't really that big of a deal for a pet...but I personally wouldn't buy from a breeder that didn't have AKC registered dogs..just my personal preference.
I also don't like that they don't show their breeding dogs on their website...usually not a good sign.
This is not a breeder that I would buy from