Spent couple more hours test fitting kit parts and new chassis. I think I should leave it aside until I get all the parts I will be using for conversion. I'm tempted to shorten front structure, but in other hand kit's front bumper isn't accurate. That means I need to have to have corrected bumper in hands first, before I could make any final decisions. Here is last mock up I've done. Doors kind of fit, but there is quite a gap at the bottom. As pointed out by other modelers, about 1-1.5 mm of material needs to be added.