FWIW, when the Soviets tested the Bf-109G-2 (on 'Kampfleistung', ie 2600 rpm and 1.30 ata), the variant with 2 extra cannons in gondolas ('five pointer', ie. 3 cannons and 2 MGs) was 3 minutes slower to 10000 m than the variant without gondola cannons ('three pointer') - 15.4 min vs. 12.3 min. The speed was 15-20 km/h lower for the 'five pointer', from deck to 10000 m. The 'no free lunch' rule applies as always.
Granted, the gondelwaffen were not as streamlined as the in-built cannons, but the Fw-190A-2 will still have one cannon more installed vs. the 'five pointer'; all of it's cannons requiring bulges to accommodate them in the wings.
Looking at the aircrafts' critical altitudes, and comparing them to the engines' critical altitudes, points us at one thing related to the BMW 801 engine installation - it was good, but it was still not perfect. It was not perfect due to it's intakes, that were under cowl, and were not providing enough of ram air benefits as that would be the case with external intake(s). Eg. the BMW 801C critical altitude on 'Kampfleistung' was at 4.6 km (2nd supercharger gear; no ram); the Fw-190A-1/A-2 critical altitude (Kampfleistung, 2nd gear, max speed ie. with max ram) was at ~5.1 km - a difference of just 500 m. For the DB 601E, it was 4.9 (engine critical altitude; no ram) vs. Bf-109F-4 critical altitude of 6 km (max speed - max ram) - a difference of 1100 m, or more than double as what the Fw was capable for.
Germans, whether BMW, or Focke Wulf, or both, were aware of the limitations of the internal intakes, and were experimenting with the external intakes - gain was, for standard fighter (Fw-190A-6) from 15 km/h at 7 km, down to 10 km/h at 10 km (on 'Notleistung').
BTW, re. comparison test A-2 vs. F-4: we don't know whether the speed runs for the A-2 on 'Notleistung' were made at 2700 rpm, or at 2550 rpm - at 2700 rpm and 1.32 ata, the A-1 (4 LMGs, 2 cannons) was supposed to do 660 km/h at 5800 m. On 'Kampfleistung', at 8000m, it was 600 km/h for the A-1 and 620 km/h for the Bf-109F-4.