impression

When I speak with potential English Customers and they tell me that at the moment they cooperate with another company I tell them this expression (obviously in order to make impression):
"When you will decide to play in the Premier League (i.e. British Football Champhionship) give me a call!"
Meaning of course that the company they cooperate is an unprofessional or second quality company while my company is a champion - first category company

Something catchy for Russians?

"Когда (вы) захотите сыграть в Высшей лиге - позвоните (мне|нам)."
There is no need in "russian-style". It is international.