Dramatic scepter + rocks,
Karn +
Voltaic Construct + big rock,
Grand Architect +
Pili-Pala,
Tidespout Tyrant +
Sol Ring + Cheerio? All of those except for dramatic scepter are mana intensive and hard to assemble (though dramatic scepter isn't very easy either without tutors). None of those are very hard to
disrupt, and you rely on LabMan to win without something abusable like
Blue Sun's Zenith to mill your opponents.
It's not necessarily a bad way to win, and most
Urza decks rely on infinite mana into
Urza's built-in
Omniscience/
Enter the Infinite combo, but it seems really slow here. Your average cmc is 2.95, but that's only because you're running FIFTEEN cheerios. That means you have to assemble one of your combos, get
Urza out, and combo off, all without being disrupted and relying on things like
Accorder's Shield to keep people off of you.
I would recommend cutting every cheerio that you wouldn't play without
Urza. Things like
spellbook can work because it works as a
Reliquary Tower that gives you metalcraft and turns into a
Mox Sapphire with
Urza.
Accorder's Shield is a bad equipment that gives you metalcraft and turns into a
Mox Sapphire with
Urza. See the difference? If
Urza gets hit with a
Darksteel Mutation or a
Song of the Dryads, you want cards that will still be useful, otherwise one good removal or lockdown spell ruins a ton of your deck's power.
You should look into a strategy that will either slow down your opponents or give you a board presence. Cards like
Karn, Scion of Urza will synergize well and give you threats,
Lux Cannon is an artifact that works as slow removal (and lets you use infinite mana and your
Voltaic Construct combo to blow up the entire board), and more counters or bounce spells would give you more interaction.
Hope this helps.