Tough, yes. But not really in a useable manner since the flaps are made of glass and flaps are the only thing that the P-40 really has going for it. The 6 50's are nice, but without flaps you aren't going to get to use them. I probably have close to 50 deaths in the P-40 last month, and in all of those sorties I can only recall 3 times that after the first time I heard pings that one of my flaps was not stuck.
I will usually only accept fire at 1 notch of flaps when possible for just this reason. If they are stuck at 1 notch you can still be moderately effective but you have to go to manual trim to slow the energy bleed. Flaps stuck anywhere else are nearly always fatal.
The good news is that once the flaps are hit, the rest of the airframe is almost indestructible. Any pings you hear after that pretty much don't make any difference until you finally fall out of the sky. The elevators are really the only thing that are at risk after that. I had a C202 jump me once after I had just finished with a 109 and was stuck at 2 notches. He saddled up pretty quickly, and it felt like I took at least 20 seconds of BB's before the plane finally disintegrated. It was almost a relief, as all of those pings were really starting to hurt my ears. Most deaths at least half of my damage list is red by the time I drop.
So tough yes, but useably tough not so much.
It is still a fun plane to fly though.