All right you guys,,, lay off the "air in air out"... I got copywright on that..... geeeezzz you can't take your eyes off anyone these days... ...



Remember that along with air in/out, you need to take into account your transmission, what gear you like to REALISTICALLY tow in, what boost pressures you will run, are you towing at altitude, mostly sea level/flats etc... .
As for injectors, I don't have experience with the ones that Dave notes (DD's)
I have run both the POD's and the 185 Bosch injectors.
In general terms running a 16cm housing using either the POD's or the 185's will work.
The POD's give you more raw HP but they will also require some 'easing off' on the pump if you want to have good all around temps. (by that I mean you may not be able to use all that the POD's bring to the table due to smoke/temps/mileage etc. )
The 185's will do a good job, and still allow a bit more 'pump fueling' and still give you good temps in general.
Stock exhaust- poor, no matter what altitude/hp rating (the same effects are compounded by stock intake filter. )
High altitude- less airflow/boost causes richer running and more smoke + higher temps.
Stock timing- generally more smoke, poorer response on throttle.
Tweaked timing- better response, less smoke, complimentary to larger injectors, better burn of fuel charge.
Pick were you want your power and were you would use most of it a majority of the time...
Bob.