Wonky Handling on the car mod Im working on.

http://www.mediafire.com/?a0icg7e6qbgc24d

Here is the link for the car I'm working on. It's pretty much ready to go, except for one problem. I've tested it ingame and the handling seems a bit "stiff" . I can't really explain it. It's not like it's the bouncy car bug, but it's close. I'm hoping it is a problem with the handling line, i'm currently using and not a problem with the model itself. 

The model is a combo of 

and 

I have resized the lightbar due to it being too small. I've also copied siren4 from the hierarchy 4 times and renamed them (siren5, siren6 siren7 and siren8) and placed 2 of them on the headlights and 2 on the reverse lights.

Since I guess this can be interpreted as releasing a mod, here are the Creds.

Model is original Ford Crown Victoria by Driver SF, modified for and converted to GTAIV by F5544.
Lightbar made by: F5544, Textures by Lt.Caine.
Police equipment made by: Rockstar Games modified to it's current form by F5544.
Main Skin textures are made by:
F5544/Lt.Caine.
Ripping From Driver SF: RacingFreak

I'll officially release it if it's good to go and maybe include a handling line in the readme