Yeah, I have no doubt that running it leaner will make more power. I think that people (including myself) tend to tune it at a safer level on pump gas rather than going for all out power.

And, of course, a lot of people like to run higher boost than where the turbo is most efficient causing increased heat and a higher tendency to knock. So, they end up running higher boost, but richen up the A/F and decrease timing to do so.

 

You can leave the current intake on as long as you get the car retuned. Pretty much anytime you add power mods or increase the boost, you'll have to retune the car accordingly. And the retune will help you get the most out of those upgraded parts.

If you plan on doing a number of additional mods in the near future, I would get those pieces installed and then have the car tuned. If you are going to tune the car yourself, read for a long time (lots of good resources here), and then make small adjustments and datalog how things change.

 

So many cars in this thread not tuned correctly...

 

There are different methods to measure fuel. Most non-US countries do NOT measure fuel octane in RON+MON/2 method which means your advertised octane is much lower than USA 93.