Cthulhu,
The P-61 was tested to have better agility? That's crazy!
But in all seriousness, it's quite difficult to believe. Better speed, yes, better climb, maybe.. but better agility? Hm not so sure. If you have a test I'd like to see it please.
malpeake,
Spitfire V's were indeed used as nightfighters in squadrons like No.111 and No. 65 sqn.s in 1941. They had no AI radar systems onboard though. It was all about following ground lights and shooting down the enemy. In fact Spitfire I's were used in a similar role during the BoB, Sailor Malan shot down a bomber sometime in June 1940.
I've heard, however, of radar systems being experimentally fitted onto Spitfire's but never used. If anyone can clarify, that'd be great.