Sports suspension for 120d coupe. yes or no?

[mudman]

I'm looking at getting a 120d m sport coupe with the auto box on the motability scheme. I'm a very lucky boy to be able to do this but won't be able to go for any options so it will run on standard 17's. Question is, do I go for sharper handling and risk 3 years of back hammering pain or hope for softer ride but always wonder if roundabouts could have been taken quicker?

I read road tests so know that smaller rim/higher profile tyres are more comfy and the sales person has said that she never orders stoch 1's with sport suspension. I need other drivers opinions!