About the bonnet model being misplaced and all, lemme quote this:
This is what I always use! Once the bonnet model is made and loaded with the car, I adjust the actor very easily with this mode. (to have access to the modes with F4/SHIFT-F4 you must first type this cheat: IBETYOUCANTPRINTCUNT) Then once the actor is set correctly you just hit F12 and hop it saves it as a new actor which you use to replace the previous bonnet actor file of the car. Typing in a hurry, hope it's clear enough!- EDIT MODE: BONNET -
F4 / SHIFT-F4 : Cycle through edit modes
1 : Move bonnet Forward (X-wise)
2 : Move bonnet Left (Y-wise)
3 : Move bonnet Down (Z-wise)
4 : Pitch bonnet Forward (X-wise)
5 : Rotate bonnet Clockwise (Y-wise)
6 : Pitch bonnet Right (Z-wise)
7 : Compress bonnet Sideways (left-to-right, X-wise)
8 : Compress bonnet Vertically (top-to-bottom, Y-wise)
9 : Compress bonnet Depthwise (front-to-back, Z-wise)
SHIFT-# : Combine SHIFT with 1 thru 9 for reverse actions
F12 : Save changes to bonnet as an .ACT file in the DATA directory.
Explanation of Bonnet Edit Mode: For those like me, who are mechanically illiterate, the bonnet is the polygon you see in front of your car from the internal perspective. This mode edits the size and positioning of this object. (C is the default key to switch to the internal perspective.)
After you're through editing your bonnet, press F12 to save your work, and you'll find an .ACT file in the DATA directory with the same name as the .ACT file your car used (as defined in the car's .TXT file). To use your new bonnet, move it to the DATA\ACTORS directory (thus copying it over the original .ACT file).
Note that some bonnets are used by more than one car, for example, most of the cheat cars use EBONNET.ACT, which belongs to the red Eagle. If you want to rename your bonnet, you'll need to use a hex-editor, such as UltraEdit, to change the internal name. (Regular ASCII text editors will corrupt your bonnet file.)
Files for the bonnet are defined under “Number of pixelmap/material/model files for this car” in the car's .TXT file. There should be three sets of .PIX and .MAT declarations, each, then a set of .DAT declarations and a set of .ACT declarations. Each set contains a file relevent to the bonnet. (This information is useful if you want to swap a car's bonnet.)
Special thanks to QTZ for pointing out what EDIT MODE: BONNET does, and what to do with the file generated by F12.