Tier 2 all the way.  Great skills class with the ability (If I read it right, of possibly dishing out 60d6 sneak attack damage on a single hit. (I could be wrong).  Is still a one trick pony, which would be tier 4 normally, but that trick is REALLY REALLY good.  Then again....after that atttack, it's sort of useless.  DUnno, maybe tier 3?

tiers 1 and 2 are reserved for WORLD altering power... not "REALLY EFFING GOOD" power. While 60d6 sneaks (if that's how it works, haven't looked at it yet) is freakin' rad... any of the max level casters will eat it for breakfast.

will post more once i've looked at it some more. 

okay, so i found the lurk and am looking at it... at 20th level, it gets 6th level psionic powers. I haven't looked in depth at psionics, but as far as I can remember, that's nothing world-altering. as for the sneaks, yes indeed if they burn all of their power points, they can do more than 60d6 on a sneak attack... however, it's the "NEXT attack" so it must be declared how many points are being burned into it before the roll is made.... don't miss or you risk burning all your points for nothing. It's a lot like the alchemist class mike Brian and i have been discussing off and on for a while... yes it can be extremely impressive and very effective at eliminating a single target... but we all know that plot characters have nasty habits of surviving things that SHOULD by all accounts kill them. 

Personally i'd be more worried about their "mental assault" augment which means they can deal 60 int or wis damage in addition to normal attack damage if they burn all their power points.

since they can use 3 augments at a time, it'd be something like this: Psionic sneak attack+4d6,  Deceptive strike target denied dex bonus, mental assault +60 int damage, and stygian weapon 1d4 negative levels for a while. 

so yes... if they burn all of their power points into one attack.... ONE thing is pretty much guaranteed to be skullfucked into the ground and stomped out... but again, this is all assuming that you can HIT your target successfully. 

looks like a cool class, and if you're looking for a one hit wonder to fuck with a DM,  i think this is it, but all in all, i don't see it being world changing. 

as was stated above, it's totally a 1 trick pony, but it's a really effing awesome trick... so i think this should be a mid to high tier 3. 

as a general reminder, depending on the time and effort invested in character build creation, classes can go up or down a tier depending on the player and campaign. I could see this wreaking havoc on a campaign in which the dm isn't willing to fiat that plot characters need to survive, but i feel like this group realizes that if a character needs to survive for some reason or another... it's going to either survive, or be brought back when it needs to be there.

my 2cents

-Z

my vote: high tier 3

I'll concur with tier 3.