RMT :D (new to competitive battling)

It's not in a specific tier or whatever, just a team :P

Spiritomb @ Spell Tag
Quiet
Pressure
244 HP/50 ATK/12 SPD/204 S. ATK
- Shadow Ball
- Hidden Power (Fighting)
- Shadow Sneak
- Sucker Punch

Salamence @ Shell Bell?
Modest
Intimidate
252 Spd/ 252 S. ATK/6 HP
- Draco Meteor
- Hydro Pump
- Flamethrower
- Dragon Pulse

Metagross @ Shell Bell?
Adamant
Clear Body
128 Def/ 254 ATK/128 S. Def
- Thunderpunch
- Agility
- Meteor Mash
- Earthquake

Skarmory @ Leftovers
Impish
Keen Eye
176 Def/ 64 ATK/254 HP/ 16 Spd
- Whirlwind
- Roost
- Brave Bird
- Spikes

Umbreon @ Leftovers
Impish
Synchronize
252 HP/ 200 ATK/56 SPD
- Curse
- Payback
- Wish
- Taunt

Vaporeon @ Leftovers
Bold
Water Absorb
188 HP/ 254 DEF/68 SPD
- Surf
- Hidden Power (Electric)
- Wish
- Protect

Is this an OK team?? :3 I'm not gonna be battling a lot..
I'm also not gonna be serious with this competitive stuff :D maybe just to battle my friends and stuff. I'm quite happy with this team though, I beat the Elite Four (2nd time) with this team (except that I didn't have a Spiritomb at that time and just randomly brought my ice punch Feraligatr to take out Lance). But yeah, I defeated the Elite Four, and all of my Pokemon were either level 60 or 61 ^^

Salamence isn't allowed in competitive battling, considering it is now Uber.
Shell Bell isn't a good item, you are better off using leftovers if you want the recovery.
You can also use Life Orb on metagross if you want it to hit harder.
Also, why sp. def and that much def evs on metagross? Metagross' defense is already pretty high, so investing in HP would be better. 112 HP / 252 Atk / 12 Def / 132 Speed is the standard spread for agiligross.

Well in order for a team to be competitive, it has to be for a specific tier. Salamence is uber and therefore banned from standard battling, so you'll have to remove him. Dragonite is the next best thing obviously, though he can't run a special set nearly as well as Mence could. You're better off sticking with DD or mixed set.

That Spiritomb lead is more suited for the UU metagame, you'll want to replace it with something that can set up SR for you since you lack it.

Agility Metagross wants 112 HP / 252 Atk / 12 Def / 132 Spe, otherwise it can't outspeed threats like Scarf Heatran and such.

You also have both Umbreon and Vaporeon for Wish support, which is completely unnecessary. Curse Umbreon is just asking for Scizor to come in unscratched and hit hard with U-Turn. Magnezone can trap Scizor locked into Bullet Punch and also remove other steels to make it easier for Dragonite to sweep:

Magnezone @ Leftovers
Naive
40 Attack / 252 Special Attack / 216 Speed
- Substitute
- Thunderbolt
- HP Grass / HP Fire
- Explosion / Magnet Rise