Please rate my Platinum team and give suggestions

Hi, I'm new to these boards. I think I have a pretty awesome team and want advice if I can make it better. I am just about to battle Byron.

Infernape - Level 47 (Modest Nature)
Nasty Plot
Slack Off
Flamethrower
Focus Blast
-Held Item: Zoom Lens

Tangrowth - Level 45 (Sassy Nature)
Sunny Day
Solarbeam
Synthesis
Ancient Power
-Held Item: Miracle Seed

Vaporeon - Level 45 (Modest Nature)
Quick Attack (???)
Aurora Beam (will later be Ice Beam)
Brine
Surf
-Held Item: Mystic Water

Dusknoir - Level 45 (Quiet Nature)
Psychic
Payback
Shadow Ball
Hyper Beam
-Held Item: Spell Tag

Altaria - Level 45 (Modest Nature)
Flamethrower
Roost
DragonBreath (will be Dragon Pulse)
Air Cutter
-Held Item: Dragon Fang

will be getting
Mamoswine (Brave Nature)
Ice Fang
Avalanche
Earthquake
Giga Impact
-Held Item: NeverMeltIce


This might be a pretty weak team but its the best one I've had...haha. Anyway I realize I rely on specials too much, Mamo will be the only physical. However I think most with high Sp. Def are Psychic/Ghost and can be taken out by Dusknoir's Payback which will always be 100 power. Mamoswine's Avalanche will pretty much always be 120 which is why I chose a nature to reduce both's speed stat.
Suggestions would be greatly appreciated
Thanks!

Sorry, but in-game teams don't require rate-my-team threads, as almost anything will work fine. This forum is for competitive teams only. Pleas read our rules if you wish to post another team, thanks :D

*closed*