Title kind of says it all, I know its not a performance car but is their any ways to add a bit more 'oomph' to my car short of putting a whole new engine in? Any turbos, filters, exhausts, belts etc.?

Thanks in advance

Pulley, headers, exhaust. I don't know if you'll be able to mingle with nitrous on a stock setup, but you get the point.

Intake and exhaust mods will give minimal gains. You're best bet is to look into remapping the ECU. I doubt it would be cost effective to consider turbos or supercharging...

Sell it and get a C55. It's the easiest way. Honestly it is much easier but if you want to keep your current car then you are looking at everything listed above but will give you little increase and it won't feel as fast.

Best bet is an ECU tune for hp and tq increase

Your car is obviously not American being a C180. Does it have a M111 or a M271 engine. Could be either in ROW. Is it a Kompressor? If it is a Kompressor engine it can be chipped to C200 spec. The move to C230 spec requires a bigger blower.

Even the pre Kompressor engines can be chipped but less successfully.