Why the original air filter? Not the best for high hp really given the increases in orifice dimensions you want for laminar flow unless you modify the box to suit!
I scaled your HFM for about 450hp seeing as you were running low compression with the 2.8 crank and that's a decent figure most aim for at the start when I do a basic set up for owners and you were going to sort the fuel on the dyno.
Most of the time, for example some of the BT S4 lot, use an HPX blow through type set up with high sensor flow capabilities;
http://www.pmas-maf.com/product/hpx-mass-airflow-sensor-ford-universal-tune-required/Although the fsi ones use the usual HFM 6;
http://www.vaglinks.com/vaglinks_com/docs/ssp/VWUSA.COM_SSP_358_Hot_film_Air_Mass_Meter.pdfthe earlier ones use HFM 5 and as you can see here there are different sizes (mass flow/venturi/connections (i.e. joining pipe sizes to suit)) between models;
http://storage.fiatforum.bg/Books/General_info/MAF/Bosch%20HFM5%20Sensors.pdfSo you can always check the flow rates against other hfm's of the same line up and, as is often the case, if the ecu's that use larger/newer ones don't use the same MLHFM maps as the ME7.1.1.'s, then you can at least get a rough idea as to how to scale the map with Bosch's mass flow figures in relation to your stock MLHFM.....eventually re-scaling as needed for an NA to FI conversion in the tune for your intended boost/hp goal.
So if you want to get more power you need more flow, more flow generally means a larger orifice as air gets hot and turbulent if compressed through a tube too much, hence sacking off stock small NA based tubes for larger ones and small air filters that don't flow as much as you want when you go for high hp! Also less pulsations etc to worry about although this is negated somewhat in the tune for fuel.
Also check any connections between HFM's if using a different brand of vehicle as the wiring/connections could be a problem, like the variances here;
https://aa-boschap-uk.resource.bosch.com/media/__uk/workshop_world/ww/news_special_workshopworld_1/pdf/sms_tips_technology_2012_nr43_en_36221.pdfSo, once you get the flow rates up and change the hardware it's then onto the air/fuelling again and ecu mods but you've alrady got the scales differences on the bin I did, pulsations etc... so mod them as required and you're good to go!
