but u are selling Blackhat service LOL!Please avoid Blackhat tactics.. That's better for client websites
how many years u want them to wait? in my exp, just buy them few package in BHW and they shall rank..Of course, you can get sued if a client pays for one thing (usually whitehat SEO) and you give them something else (blackhat SEO). The case would be further aggravated if they lose their rankings and their investigation leads them to the conclusion that the blackhat SEO you did is the culprit.
Bottom line is, don't use blackhat SEO to rank the sites of clients that don't want blackhat SEO.