Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
While certainly not in the hi-alt category where P-47M/N, P-51H, Spitfire 20s/Spiteful, Hornet or Ta-152 belonged, it was not a dedicated low-alt fighter either. It was in league of F8F-2, Japanese top-league prototypes of 1945 (I'm not including Ki-100 or A7M here) and a bit better than F8F-1, P-63C, Fw 190D-9, F6F-5 or even -6, or any of the Soviet late war fighters.
The air-cooled installation of the Fw 190A was probably still very competitive in 1945 (even if not ideal). The BMW 801 itself was not, even of we talk about 801S or 801F, especially above 20000 ft.
I'm no sure we can compare air-cooled engine with liquid-cooled engine installations, even the ones looking similar. WIth that said, Focke Wulf was calculating that cooling drag of the Ta-152 (including the intercooling) was 80% of the cooling drag of the BMW 801 - despite the Jumo 213E and DB 603L offering superior power at all altitudes.