T5 or D4 in C70?

Which engine would you take if you didn’t drive more than 15000 euros a year, mostly extreme short-range operation, especially in winter often only 2×1,7km of city traffic, because the cooling water indicator moves just when I park the car. On the other hand rarely, but then quite fast, on the highway. Then I use the 240, which my SLK can run, not out, but constant 180-200 already, if it is possible. I tried the D4, caught me at the frequent full-speed give. Although with diesel and automatic the power would have been enough, the final speed would have been just 210 with even after Tacho without a start just a little too little. I would have a diesel – if this did not cut the lifespan too much, chiptuned. Two Volvo dealers advised me on requests rather to the petroler because of the particle filter. For the diesel speak the lower fuel costs (would be important to me nciht), the durability? and the relaxing engine characteristics. What do you mean?