2009 Vauxhall Corsa Vibrations through steering wheel

I bought the car around 2 months ago and have always had vibrations through the steering wheel. It feels like it's originating from the passenger side. I have had the wheel alignment checked and the balance also. I also found I had a cracked rim which I had replaced too. I had the ball joints replaced as they were slightly corroded too. The vibrations, since I had the work done, have definitely got better but they are still there. Any ideas what the problem may be?
(P.S: The car has aftermarket suspension already installed when bought)