Dunno... I will test it though.
One thing for sure is this: A P38L will eat a Tempest alive in a scissors while at high speeds... even when loaded with %50+ fuel, 2/1k bombs, and 5in rockets. I was part of a mission when I was intercepted by a Tempest and my only thought was to get him away from the allied bombers so I went nose down (we started at 20k) and turned °90 away from the bombers. The Tempest followed me down and somewhere in the mid 400's I started to shake with him 800 behind me. I gave him his better roll and took him right °90 and then let me catch me, he was 600 behind me at that point. I then took him °180 left and cut throttle a wee bit... and he went right on by. I hit the throttle and kicked on WEP and followed him up (I had forgotten about all the extra weight by this time), I got to within 400 yards of him when we both stalled out (after I missed my shot

). We both rolled back under and did a full loop where wouldn't ya know it we were setting up for the HO. He won thanks to my bad aim that day. However, I did see him trailing oil after we collided. So ultimately, I accomplished my mission and get him away from the bombers.
I can certainly vouch for how well the P38L can roll at high speeds, heavy or light. Wowza.