To each his own I guess, in my case:

1. for P2,500, I get to use superior plug indefinitely (will probably outlast the car) so it's still cheaper than stock in the long run. ignite better - more torque.

2. open-cone vs. stock filter really makes a big difference, except for the noise. the filter charger should actually make the filtration better if maintained properly. breathe better - burn better.

2 cent's lang po.