The only mod you will need is put on a set of Hogue grips. Buy the ones without the thumb rests so that you can shoot with either hand (sorry you don't have this option with the 22/45). Put 1,000 rounds through the pistol and then decide if you need to do any more mods.
for the Hogue grips. They whould be all you need for an "entry level" gun. If you decide you have too much money floating around, a Volquartzen kit may be in order, but for the money, you'ld be better off saving up for a Model 41. Better yet, just buy more ammo and practice.