bad effects of new gears
 

im gonna get my gears changed to the 4.10 this weekend is there anything negative that will happen to my car

No, have fun.

The only bad effect is that you may be replacing your rear tires more often.:Woot:

Don't forget the friction modifier!!!!

higher rpms at highway speeds... shouldn't be too bad

I've really enjoyed the 4.10s I had installed a couple of weeks ago. I put them on my auto GT daily driver. I don't drive on highways that much, mainly in town use and I've actually gained 1-2 mpg. I think its because I go through the lower gears faster and get into overdrive sooner at lower speeds. Enjoy the gears, it'll certainly make a huge difference.

where to get them
 

so does anyone know a good site to get the friction mod andd the gear kit

I beleive mustangtuning.com offers the gears

how much are you paying for your 4.10s? im thinkin about getting some too. are you buying brand new ones or taking some good condition ones off a scrap car?