Select all the faces that for example should be mapped to the "roof" part of your template.
 Then SURFACE...->MAPPING...->RESET UV -> ASSIGN UV

You should one window have now set to "UV Mapper".
 Enable "Objects view". You now can move and scale the object in "UV Mapper" window to properly assign it to the template. 
You'll notice in "3D" window how the mapping changes/moves when you move/scale the object in "UV Mapper" window.

This you can do with all faces of the car until you have them all assigned to the template.

It's a little more work than using Remapper tool, but it a) more accurate and b) IMO the better way.

If you want to have the mesh displayed how it fits to the template,
 select all the faces that are mapped to a certain TGA then SURFACE...->MAPPING...->ASSIGN UV .
 In "UV Mapper" view you'll now see the mesh on the template
Once you have selected faces for the hood for example you need to open material editor,
 at the top you'll see a drop down where normally your textures will be listed. 
Seeing as the car had no texturing you need to create a copy of the <default material>. 
Beside the drop down is two buttons, Delete and Copy, 
clk on copy and then open the drop down and select the 2nd (closest to the bottom) <default material>.
 You can rename this to anything you like. Now import your texture as you would normally, 
ie check primary texture/load map/add. Next step is different, instead of clicking on "APPY CHANGES" click on "ASSIGN TO SELECTION" then click OK. 
Now your ready to follow Karls above steps:)