Hi,
Yes, the C250TD is a five cylinder, turbo charged and intercooled, developing 150bhp as standard spec.
Personally I think it is a better engine than the early 220CDi's although no where near as economical. The more recent 220CDi's have been uprated and are much better. The 250TD feels really eager, no noticable turbo lag and has a really nice growl to it when pushed hard. From memory 0-60 is claimed by MB to be around 10.5 secs, but MB seem to be a bit pessimistic in their figures. A chipped 250TD really does fly!!
The only thing to watch out for is bad starting in cold weather, this is because it is likely to be a glow plug, whilst not an expensive part they are difficult to get at to change but not beyong a competent DIY mechanic. Also the O-rings around the filter head perish and lead to air ingress and poor starting.
If you want economy and can afford the extra, go for a newer CDi, if you want a good compromise between performance and economy you will find the C250TD hard to beat, expect to average around 30-35mpg.
(Actually the VW/Audi TDi's, especially the 130/150+bhp units are amazing, better than petrol performance with 50+mpg!!)