Required Stats for Kara (WoW - Rogue)

Weapons:

Your main hand should always be upgraded first, obviously, this is where your dps is affected the most. The slower the main hand weapon the better, for all builds, it gives larger backstabs, mutilates and sinister strikes. The optimum speed for your offhand changes with your build, for example mutilate builds benefit from another slow weapon in the offhand, whereas combat daggers benefit more from a faster dagger.

Ill sugguest some minimum spec weapons for starting to raid kara, swords and daggers, as these are the most common used raiding weapons.

Gladiators Shanker/Shiv or Gladiators Slicer/Quickblade are available as PvP rewards. These are easily attainable for a couple of weeks work. Equivalent weapons are a minimum to begin raiding. The +stats on these weapons are also very desireable, all offering attack power, hit rating and critical strike rating.

Other alternatives would be:

Daggers:

http://www.wowhead.com/?item=29182 - Exalted with Keepers of Time
http://www.thottbot.com/?i=60357 - Dagger - Arcatraz (Heroic)
http://thottbot.com/i=57959 - Dagger - Craftable, epic pattern
http://www.thottbot.com/?i=54569 - Dagger - Exalted with Scryers

http://thottbot.com/i=59016 Is the VERY minimum, your dps will be comprimised, but this dagger can be picked up cheaply from the AH if you have nothing else.

Swords:

http://thottbot.com/i=55308 - Exalted with Aldor
http://thottbot.com/i=58942 - Black Morass

You should aim for 80dps to raid Kara, I strongly reccommend you take the time to get the arena/PvP weapons. Even the Season 1 weapons with 88.1dps and excellent +stats are on par with the weapons that drop in the early-mid parts of kara, and can be easily obtained. Season 2 weapons will easily beat anything dropped in Kara, and bothering to get these is one of the easiest ways to see your raid dps shoot up.

Weapon Enchants:

The best rogue weapon enchants for increasing raid dps are +15agility, +X weapon damage and of course, mongoose.

Now its probably not worth spending all your money on 2x mongoose enchants on weapons that will be replaced anytime soon, but if you have the gold, its the thing to do. Enchanting both Season 2 weapons is worthwhile, as you will not find a better replacement until way after Kara, so if you have the gold, go ahead. +15 Agility is a lot more affordable, and will also give your character a stats boost.

Next I'd say +weapon damage enchants. +6 or +7 damage on every attack will of course add up.

If you cant afford a mongoose enchant, or want to save your money for enchanting a more suitable weapon, then Id recommend enchanting your MH with +7weapon damage, and your offhand with +15 agility.

DO NOT enchant things like fiery, icy etc etc, yes, they're pretty, but their effect at level 70 is minimum and just not worthwhile.

Stats:

Right, youve got your weapons, now its time to concentrate on what stats are most usefull to improve your raid dps.

Agility

Of course, stack it, its out main stat.

1 Agility = 1 Attack Power
1 Agility = 0.025% Crit (40 Agility ~ 1% Crit)
1 Agility = 2 Armour
1 Agility = 0.0438% Dodge (23 Agility ~ 1% Dodge)

Hit Rating

One of the most important stats is hit rating. Your dps will be non-existant if every other attack misses.

(To maximise hits in combat, all rogues, dagger or sword, should attack mobs from behind, this eliminates block and parry. )

The minimum amount needed varies between builds, but if your hit% is +8% then this means every yellow attack will hit. But of large chunk of your dps will come from white damage, through slice and dice, so youll probably want more than this anyway.

At level 70 15.8 hit rating = 1% hit

Therefore the very minimum hit rating is 127.

The talent "Precision" in the combat tree is a must, and raises hit% by 5. This is used in all raiding builds.

Attack Power

Every 14 points of attack power you have, gives you +1dps. For Kara Id reccommend a minimum of 1400 attack power, which gives +100dps.

A crit chance of 20% is minimum. 25% is reccommended. 33% is the maximum ever advised, after this you would be better off stacking other stats, such as Attack Power.

Summary:

Therefore, minimum stats are:

127 Hit Rating
1400 Attack Power
20% Crit Chance