Call me boring, but after taking the Cup on it's first trackday I came away thinking about mods, but not a single one involved power. If I had a choice of mods I'd go for -
Consistently powerful braking - so uprated lines, pads + discs
Consistent feel for what the car is doing - decent bucket seat, harnesses, decent grippy steering wheel, decent suspension. Happy with the handling on the Cup but you may want decent springs/shocks added to yours.
I wouldn't bother wasting your money on trying to get more power from it, but then it's easy for me to say that with my 2.0 lump.
Just my views of course.
For power you could always consider an engine swap?