They're are alot of varient's of the Toyota Hilux but the most common difference are with the engine as the Thailand/European/Japanese market offer's the 1KD-FTV and the local market (Toyota Indus) offer's the 5L-E)
The 1KD-FTV (D-4D) is a 3.0L (3000cc) I4, common rail diesel engine with a variable geometry intercooler it's one of Toyota's latest engines, it produces around 170HP & 260 Ib.ft of tourque. It is also considered to be one of the best diesel engine's currently avaliable in the market across the world.
The simple Hilux which is offered by Toyota Indus is a 5L-E I4, 3.0L (3000cc) Diesel, EFI version, it's output is around 96.5 HP & 141 Ib.ft of Tourque.
Single cabin and double cabin is optional with the 5L-E, the 1KD-FTV Hilux Vigo's mostly come from Thailand which are almost loaded with all the necessary option's.
If you consider going for a Hilux, go for the Hilux Vigo with the 1KD-FTV, it's a really good engine but with the latest diesel engine technology but it's really sensitive aswell, Fuel pump's across Pakistan which have Diesel pump's contain a high quantity of lead contain in them which is quite harmful to the 1KD-FTV as the fuel coming from the fuel injector's enter the common rail which supplies fuel to the piston's which lead's to engine fault's and replacement. Their is currently no cure for it here but, what you can do to keep your engine running nice and smooth is get a Air/Fuel test from time to time.