Hi there,
I had a Sportrak for 2 years until last summer, great little motor. I had a later model with the 'face lift', so it was the injection model rather than carb engine. Very nippy, much quicker than similar cars like Vitara's. Great round town, and I did loads of motorway miles in it just fine (again, goes quicker than you'd think, but supps loads of petrol over about 75 mph!)
Got approx 28-29 mpg round town (London traffic tho!) and up to 33 on a steady 70mph run.
Parts new are a bit pricey, but some good specialist used part suppliers. Having said that, they're solid little trucks, so nothing much goes wrong. For tech help and advice try
http://www.daihatsu-drivers.co.uk.
Off-road mine was very capable with just all terrain tyres on it. Not much available to modify it like you can with Suzuki's and Land Rovers, but can modify them with a bit of imagination!! (again, Daihatsu Drivers or similar and see what others do if you're interested).
Look out for rust on the chassis, mine rusted by the rear leaf spring hanger, but got it welded cheap enough. Some are bad for rust, others (later ones?) are OK. If its the top-spec model with 'adjustable dampers', don't be supprised if the wires are taped up and standard ones are fitted - originals cost an arm and a leg and no real benefit! Watch out for smokey engines too.
All in all a great car - I loved driving mine on and off-road, a really sporty little truck (got a grand vitara now, and altho not that slow seems really sluggish in comparison). They've got stiff suspension, so quite a bumpy ride, but because of it theres no real body roll and you can chuck them round corners!
Find a good 'un and you'll love it!
Hope thats of some help! Best thing is to go and try one, and shout if you need more help!
Regards,
Nat