Who is running what? I fancy something that's a: effective and b: looks more aggressive.

 

Any suggestions please?

 

They're all for show. The car runs too high for a diffuser to work with any effectiveness. Just buy the most outlandish one you desire based purely on aesthetics and cost (and what it's worth to you).

 

 

But don't - they look awful!

 

Even a nice satin black, unextended one? 

Halfords sell tins of paint.

 

I'm not convinced the S1 looks better with extra fins and whatnot at the back. It's such a simple shape any aero addenda seem to detract from that. Your car is a "pretty" version of the S1 too, so I'm not sure masculine/aggressive mods would work. Had you bought an orange or yellow black wheeled track special then maybe, but you have dainty little thing (!).