Some fictional history:
The Bf 109 K-11 entered service in late 1945 with a new Daimler-Benz DB 612A engine, being one of the fastest piston-engined aircraft of WW2. It has the same fuselage as the Bf 109 K-4, the only difference is that it has a bubble canopy, 13 mm machine guns replaced by 15 mm cannons, taller vertical stabilizer and it has air brakes, it's also lighter, faster and more maneuverable.

The aircraft it's armed with:
- Two 15 mm MG-151/15 (290 ammunition per cannon)
- One 30 mm MK-108 (65 ammunition)
- Four 125 mm rockets
- One 250 kg bomb

Controls:
- Change vision position to try to see under the nose with key 2
- Extend air brakes with key 3
- Drop bomb with key 4

Flight perfomance:
(All the perfomance without the suspended armament)

Max speed in a straight line at 3000 ft: 527 mph / 848 km/h

Turn time at 300 mph:
- Vertical: 16 s
- Horizontal: 14 s

Speed to take off:
- Without suspended armament: 110 mph / 177 km/h
- With suspended armament: 125 mph / 201 km/h

Speed to land:
- Without suspended armament: 120 mph / 193 km/h
- With suspended armament: 140 mph / 225 km/h

If you want, remove the suspended armament to be only a fighter.
Don't brake hard when landing or you will break the propeller/roll over

I thought it would be nice if the rockets were actually cannons with low speed

based on this

Others:
Bf 109 K-11 (MK-108 gun pods)
Bf 109 K-11 trop
Bf 109 K-15