Not exactly. מ can also be "than". As in: יותר מקילומטר, more than a kilometre. Literally מדי means "than enough", but you can say things like גדול מאפס which means "bigger than zero", חזק ממני "stronger than me" etc. In Hebrew the "more" form of an adjective is the same as the regular form, we often use יותר but leaving it out is allowed, and so טוב מדי is "better than good enough", the same as טוב יותר מדי or יותר מדי טוב which is I think what I usually say.
I agree with Joel. Also, to say "this team is good too ", as in, this team is good as well, you would say הצוות הזה גם טוב Although I think you could put גם also at the end of the sentence or in the beginning, depending what you want to emphasise. I'm not a native speaker, but I'm pretty sure this is how it is.
Well, הַצֶּ֫וֶת הַזֶּה טוֹב מְאֹד this team is good is simply a laudatory statement, but הַצֶּ֫וֶת הַזֶּה טוֹב מִדַּי this team is too good means excess. This could mean that one can not compete with them or more ominously that something is foul in appearances, like in יָדַ֫עְתִּי שֶׁהַדְּבָרִים הוֹלְכִים טוֹב מִדַּי בַּזְּמַן הָאֲחָרוֹן I knew things are going to good recently or הָיִ֫יתָ רַקְדָן טוֹב מִדַּי מִכְּדֵי לִהְיוֹת יֶ֫לֶד סְטְרֵיט you were to good a dancer to be a straight boy.