If your M3 body makes you feel better than Nikon body , why not ? But LTM Nikkors are the exact copies of German designs and they are EXCELLENT. I dont give a dam to plastic or 70s Nikons but LTMs are super. Summicron is very expensive and it pays you back unless if you have money to pay back to bank.
Or you will forced to sell it and be an enemy of it. This is frequently observed at this forum.