Is the 2009 (09) 1.6l 113 bhp zetec S engine worth moding?

Like i say i cant afford to spend a fortune just want a bit more power as much as i can squeeze for as low a cost as possible.

Can anyone tell me mods and give a rough price and rough bhp increase.

If i got summit like 20-25 bhp increase would it made much of a difference? sorry for the daft questions, i've only ever had a few cars and none of them have been quick just small cheap cars to be honest and never moded them.

Cheers