Hi I have a HL2 which I personally imported with UK service history from the dealer 55,000 miles when imported , my under carriage doesn't have any rust and UNLIKE the one's sold locally which the under carriage is painted. And it drives like brand new no noises etc...
The biggest issue is the mileage as most of the ones which are in SL for sale have done more than 100,000 miles + but the meter reads around 30,000- 40,000 miles. No point only looking at the BV certificate as that can be altered in UK inseams , always ask for the service history otherwise you are asking for trouble .
UK imported hilux have more options such as dual air bags, Rear Diff lock, headlight adjusters compared to Thai spec. If you are a off road fan the Diff lock comes in very handy .
Cheers.