Future over Testors metalizer paint question

I should know the answer to this question and probably do but I'm going to ask it anyway. I've just finished painting and buffing with Testor Metalizer paint. The results are IMO wonderful. I can see my reflection in the finish. Now I'm ready to apply decals. Should I go ahead and decal or should I shoot a coat of Future over what's there now. I'm hesitant to do the Future because the finish is already really nice and I'm afraid I'll screw things up by applying the Future. With my past experience using Future, it's always a hit or miss thing.  Never have really gotten the hang of applying it.  Sometimes great, sometimes not so great. Any takes on this? Thanks on advance for suggestions/comments.

Steve