Do not remove the down-thrust. Trust me. I did it with my trainer years ago and had a difficult time controlling it. The next day I put it back in. As mentioned by Deadeye, the flat-bottom airfoil has a natural tendency to climb. The lifting ability coupled with down-thrust is why trainers can fly so slow.
If you take out the down-thrust, you'll have to add a bunch of down elevator. Flight will not be easily predictable. You will not like it.
You could experiment with decreasing the wing's AOA... but then it really wouldn't be a trainer/easy-flyer anymore. You'd be better off moving up to an intermediate type airframe.

If you insist on trying it, cut two equal door-wedge shaped triangles and put them between the engine and mount to remove the down-thrust. Or, you could place a few washers behind the lower edge of the mount and the firewall.