If they are wired in parrallel you can add different wattages without any problems.
If you have a MPPT
controller you need to keep the voltages similar. Vmp should be within 0.5v. If you have a none MPPT
controller this is less important, but they will all need to be nominal 12v panels with 36 cell, not high voltage panels.
Your controler and wiring
may also need to changed.