not as fast as an LA7 and will not acclerate as much, it does not have a great wepons loadout, but it will climb like an angel and is much lighter and more powerful then a 9u - which means it will be very fast.
A quick check shows
La7 power 1850hp (WEP) gross weight 3315kg ratio 1:1.79
Yak9U (VK107) power 1650 gross weight 3205kg ratio 1:1.94
Yak3 (VK105PF2) power 1290 gross weight 2675kg ratio 1:2.07
The GPW Yak3 is not more powerful than the later Yak9U and would not climb or accelerate any better or have better top speed. It may turn with and in side the La7 (21sec) and better than the Yak9U although it had less wing than both of them.