Re: To Port or not to Port...
If you port the 20, you will lose a lot. The roundness dies and you get more of a thud. Put me down for changing the stock logo head with a non ported Ambassador head of your choice (clear, white, black, etc.) They just sound better than stock heads.
If you can, I'd buy a pre ported head too, just so you can experiment, or port the existing logo head because it's a cheap head. You really have to experience the difference for yourself, on your drum, in your house, to really understand what porting will do, to your particular drum.
I was a ported guy all my life. Now I am a non ported guy. The bass is just so much fuller. I never buried the beater. With a non ported head, burying the beater...it's hard to do do, for me anyway, without getting the multiple bounce thing going on.
Ever port a tom reso head? I put a 1" hole in a 12" tom once. Totally killed the tone. Same thing on any drum.