Me too, mine had $1500 invested in it and it made 442rwhp and 460rwtq. It was badass, but the vette is on the exotic level and the cobra will never be. Im happy with the swap from the cobra to vette, but the power was nice.

 

Differences = cross drilled, larger brake rotors, more cooling, stiffer suspension, larger sway bars, supercar tires, a quicker gear ratio, and I think thats it. Extra $1700 or so. How much difference can I tell driving? depends who you ask. Stiffer suspension makes a difference I hear, but i wouldnt know...havent driven a non z51. i like my ride just fine... i like the cross drilled rotors, right now mostly because it looks cool. if/when i start tracking the car, the better braking and the extra cooling will help too. supercar tires are great as well, but i dont want to replace them with more supercar tires after 10k miles as i hear you have to do since they are so soft. i'll stick the stock c6 tires on instead. its all personal preference. z51 owners will all tell you its worth it. a lot of non-owners will tell you its not worth it and theirs is just great as is (or with the f55 magnetic selective ride). for $45 -$50k, whats another 1 or 2k? its worth it when you sell it again in my opinion. also have no idea about if/when incentives will come again from GM. forum vendors may know...but DEFINITELY sell privately. i did not want to deal with the hassle. my dealer left me no choice but to do sell privately, and i am glad I did and will never trade a car in after this experience.

 

My opinions. Sell your Cobra on your own. The dealer will not give you what it is worth. Wait for GMAC 0% financing. Over 6400 2007 Vettes plus some 2006s on dealer lots and sales are slow. They are gonna have to do the zero percent financing again. Waiting will also give you time to decide which options you really want. If local dealer will not sell for invoice then find another who will.
Good luck,
Jeff