There were three completely silver VX's made, well I mean silver coloured and silver painted cladding, they are recognizable by their black oem wheels and leather upholstery.
If yours doesn't have these trademarks, it's a "self painted one".
By a converted tank you mean, an extra tank for the lpg right?
Check the front rotors (Jap version ones need to be replaced quicker)
Check if the monitor works in reverse.
For more not Jap version specific VX problems I'd like to refer to the serarch option.
Good luck!