Update: Received confirmation from Cody at TORhead that they'll be adding a disclaimer. I commend their professionalism (and look forward to continuing to use their database/tooltips).
TORhead's tooltip numbers are (currently) flatly inaccurate representations of the damage your abilities will do as a level 50 Sniper. Do not use their damage estimates either to theorycraft or attempt to justify a talent build. If you see anyone using these numbers where Sniper is concerned, stop them!
TORhead calculations currently do not account for buffs to basic damage, crit rating, surge rating, and other facts of life that have a large impact on Sniper damage at level 50. They are no good for you and have faint basis in reality.
Edit: Added some "overestimates." Snipe is not as good as TORhead has it calculated.
These damage estimates are based on my experiences as a 10-month general tester in the SW:TOR beta, current as of the launch build while using subpar PvP gear and playing with and against many other ACs and levels on Darth Malak server.
My "average" Ambush numbers were 3k with regular crits of 3.5k-4k.
Average hits for 2.5k-2.8k and crits for 3.5k-4k.
And two overestimates:
Did 800-1500 damage for me ... yeah. Wow. I didn't realize this was that far off. No wonder people on the forums have been so confused.
1500 on the initial detonation; Engineering an additional 500-700 per Cluster Bomb detonation. So about 3-3.5k.
Please resist the temptation to attempt Sniper theorycraft with TORhead numbers!
By all means continue to use their wonderful talent calculator and their otherwise accurate "descriptions" of abilities, though. The energy costs and the CDs, respectively, are correct (and it is the most accurate database in general).