I have a Gen 1 996 C2 Tiptronic (2001, 3.4). I've had it for 4.5 years and covered 40,000 miles in it since then. Total mileage is 97,500. During my ownership running costs have been very low - one battery, two sets of rear tyres, one water pump, discs and pads all round (largest single expense - £1000) and one sun roof seal. Servicing is once a year by a local independent specialist and rarely over £300 + MOT.
I love it and can thoroughly recommend one. Buy carefully - get it checked by an independent before parting with the cash. Don't buy too cheap.
There are all the scare stories regarding engines on the internet. By and large the early engines will have been sorted by now. As a guide a Hartech rebuild will cost around £3500 - I've just spent almost that on my Norris Motorsport CVH rebuild for the Morgan - and that was nothing super special (full strip, skim, solid lifters, cam).
Going forwards over the next year I'm budgeting for front tyres (approx £450) and silencer boxes in SS (approx. £800 fitted) - a normal service and a contingency for radiators (I always have contingency for radiators)!
These cars are surprisingly affordable to run say 8,000-10,000 miles a year and, although I would never change the Mog (27yrs and counting), there really is no comparison with 4.5 seconds to 60mph, 300+bhp and under 1400kg. The only thing is - they come into their own once the legal speed limit has been reached!!