I can start with "I dunno much about cars"
I heard that the GXP will be offered with both manual and auto tranmission, but they mentioned somethin about the auto bein a 3:27 rear axel and the manual 3:70 rear axel!! wat do these numbers mean? and in regards to performance!?

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Current: 2006 Grand Prix GT S/C
Waiting for the G8 GXP

Higher the number, the lower the ratio, delivering more power and torque at any given speed (as engine is turning faster) Just swapping out the 3.27 for the GT's 2.92 would make it faster. With the GXP and the differences between individual gears a chart will help.

Notice that by multiplying the rear-end final drive ratio times the gear ratio of the transmission we get an overall effective ratio. Higher number means higher engine rpm (usually higher hp and torque) at equal mph with same wheels. In first gear an auto GXP has a ratio of 13.18 compared to the manual at 11.14, and in second 7.72 to 7.66 . Not until you hit 3rd does the manual have an advantage, and they are almost even in 6th, but not quite.

What's this all mean? A little heresy, as a duel from 0-60 may possibly be advantage - auto. Especially if it can be achieved in second gear. Even going to third it will be early in the revs and the race may still go to the auto. The manual will pull ahead from there and has a good chance of gaining a slight edge by the time you hit 110 in the 1/4 (13.0 seconds out).

Except that it's computer limited, a manual equipped GXP will have a slightly (by 1 or 2) higher top speed flat out. Both of these ratios, however mean tons more gas consumed, even if they were paired up with the L76 instead of the LS3. in sixth, the auto LS3 engine will be turning 2.19 engine rpm/wheel rpm while a GT's L76 will turn 1.96. Assume a steady state cruising speed at 60 and possibly 1800 rpm in a GT, the GXP will be running over 200 rpm higher. Faster, but definitely more thirsty.

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All i can say is that, u know allot about cars
so bottom line, the auto would b a bit faster on a 0-60mph run!
U also said that the manual picks up on the 3rd gear, then the auto takes the lead again ?

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Current: 2006 Grand Prix GT S/C
Waiting for the G8 GXP

4th and 6th gears each have such a slight ratio advantage in favor of te hautomatic, but are less than the advantage/manual in 3rd and 5th to have much affect. Two other things will come into play, hydraulic losses in the torque convertor in the automatic counteracted by clutch slippage in teh manual. It'll take recorded track numbers to be the "tell of teh tape" but if Pontiac's experience with the Solstice is any indication, under the control of an average driver (and we all are unless we get a paycheck for driving) an automatic Sol can be .1 second faster to 60 than a manual. Different vehicles, engines, trans, etc but the idea is the same.

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Thanks for the info
I'm waitin for the GXP but still dunno if i should get an auto or a manual i guess its just a preference after all!

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Current: 2006 Grand Prix GT S/C
Waiting for the G8 GXP

Thanks for the ratio info Chief, The main difference between the two trans. will be driveability. The manual is way more fun but,as seen by the CTS-V guys,you are more likely to break stuff. The ZF rear that comes in these appears to be very similar to the unit in the V and if you listen to or read some of these idiots that take their Vs to the drag-strip,all they do is complain about wheel-hop but keep up the 6000 rpm clutch dumps and then blame GM for under-building or scrimping on the Diff. unit. The ZF is a very good unit but not designed to be exposed to such shock loads. The German cars don't have diff. problems.
I am sure that some of our specialty shops(Thanks Guys) will come up with fixes for any shortcomings in the suspension/drivetrain areas.
As for performance,The 09 CTS-V turned the fastest production car lap ever on the Nurburgring with an Auto. Trans.