Can anyone tell me the pros and cons of the 3:55 as opposed the the standard ratio thatt comes with a manual trans?

 

i might be reading your question wrong but manuals come with a 3.55 gear in the rear. only autos and V6's come with the 3.31 gear. With my car, if feels like after 3K rpms is where the power starts. Ford put 3.55's in it, nice, but low end kick is sorta weak to me. That's why 4.10's will be soon for my car.

 

From what i gather, 3:31's are standard equipment in the 2007 GT's. The 3:55's are a $100 or so option.

 

Right you are.. for 06 355 was standard for Manuals and 331 for auto...For 07 all come with 331 and 355 is a option, Ford just wants to make a few bucks on that one i guess...i love 355 its perfect for me, i guess they (Ford) feel 331 is a joke and everyone will upgrade it..who knows..

 

3.31s became standard, even with standard transmissions for 2007. They offer slightly better gas mileage (on the highway). However, it hurts low end power slightly. Unless you want to drag race alot (which you would want 3.73s or 4.10s anyway), the 3.31s will do just fine. I recommend test drivng one with each gear to draw your own opinions.

 

Its no joke. My auto with 3.31 is no slouch. It'll burn rubber from a dig. Even so I would still like to get 3.73s.

 

I put in 4.10s right after I purchased the car. They were great on a stock build. After installing a KB blower I think they are a bit too tall. It is just to short of time going from 1st to 2nd. I have 3.73s coming from FRPP today and will install those, which should be just about perfect. 4.10s are the way to go if you are staying stock or going with a CAI and tune. IMO the 4.10s are just a bit too much for high horsepower engines unless all your interested in is 1/8th or 1/4 mile times, or 0-60 times. Just MO.

 

there a waste of money, just have 4.30s put in down the road

 

There are no cons to the 3.55 gears for a street car, pre 07 they were standard.
maybe you will lose around 1/2 mpg on the highway, other than that i would say its the best 100$ you could spend.