So let's sum it up.
4. A company specialized in tuning Fords, located in Melbourne, whose name starts with the letter H and is an acronym plus another word. It's neither HP Factory nor HP Tuners.
22. A tuning company located in Western Australia, whose name starts with the letter A.
When I'm looking for companies that fit these criterias I keep on finding the same rejected companies, so please fellow puzzlers help solve these last two mysteries !