Summits were not offered with PT in 05, so you won't find much help over here.
FWIW, my 04 800x (DPM) came with 400's. Unless you're below minus 10 F, you can take these to 380's in the 04's, at least at higher elevations. Now, perhaps they increased the main size in 05 for the PT, to provide more cooling for the deto sensor, but a DPM recalibration would be necessary. Interesting change, if they went to 440s. Then the 05 DPM map would be leaner at any given air density.
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