Jayraddd wrote:Exhaust note + slightly better gains from a Kido tune.
'No point doing mods like that on N/As bla bla'....
I'm aware what car I'm driving, I dont want a turbo.
Sorry, just in before the rest of the comments..
I'm not saying there's no point.
You're clearly aware then of the limited gains that are possible in terms of power. Of course, power's not everything (and I do appreciate the linear nature of an NA power curve, my previous car was a narrow angle V6 that put out 150kW/270Nm stock, tunes and exhaust work could take it to about 165kW/300Nm at best).
To answer your original question - I'd be surprised if you could do much damage as such with the headers and cat, the ECU will learn a bit about the different system and adjust partially for it, but the best gains will come out of getting that tune done pretty quickly afterwards. Kido tunes aren't at all expensive though, so you shouldn't need to wait long to get the tune done (and you can also work with Matt to do the tune remotely).