Gettin' a Polo 1.2 9N 2005 - Modify or Not to Modify?

[Saintonis]

Was thinking once I purchase my second car (VW POLO 1.2L, 05 9N) , would it be worth modifying the engine to make it a "tad" more nippy? I've driven the 1.2s before and I think my Previous 1Litre 6N was far more nippy than the 1.2 9N.
Either that- Or I was driving like a numpty in a sluggish death trap of the 6N- lol!

Yeah I'm not great with the knowledge I have about cars- However, I'm a Very fast learner! Don't need things to be broken down to understand as I am not thick (I hope!)

But yeah, would it be worth doing any mods to the engine or Shall I just stick to having fun on the cosmetic side of modifying?

-Help a Newbie, Be happy.