US made cars are to be found here hardly. Toyota Landcruiser which is manufactured as Lexus LX470 in USA is popular. Engine size 4200cc diesel would be excellent to cruise on Pak roads.
Hummer H1 has also been seen in Lahore and Islamabad but main problem with US cars is that they are LHD, and due to not having dealership here, spare parts and servicing are problems with US brands.
CNG system can be installed in almost all petrol cars easily, however, diesel engines are a bit difficult to convert as their kit is more expensive than petrol engines. Other thing is price of diesel, which is almost half of petrol, so not too many people are interested to convert a diesel engine to CNG.