I wouldn't bother with the 8v personally, go 16v all the way!
On mine It's upto £50-£60 for a tank, I get about 270-300 miles averaging around 28-38 mpg (town/motorway)
I bought mine for £900 with 85K last year, now upto 103K with no serious issues, oil leak, new alternator & have done the cambelt for good measure. Everything else I've done has been cosmetic/performance improvements!
Mileage goes hand in hand with good history, so as long as it's been serviced reguarly etc. you'll be fine.
MK3's are heavy cars, probably under-powered, the 8v is only 115bhp, 16v 150bhp, & the VR is 200bhp but they arn't slow cars, plus a couple of little extras will steal you some extra horses!
The book top speed for the 16v is 137mph, & I've had mine upto 130mph before, not at all scarey!

Whatever way you look at it's going to be an improvement over a 1.3 Fiesta, might cost you a little more to run but the benefits out way the negatives so go for it!!
