this is one of my all time favorites!
For me I'd start gentle with this one as they got the design pretty right first go. Oh cause it needed to be built with the right materials first, but then, cause I am a night fighter fan, loose the antennas. Either fit a FuG240 "Berlin" radar or the FuG244 "Bremen", a much more streamline setup.
Next the engines needed beefing up, maybe something like the DB632 (DB603N) with contra-rotating props or the DB623 (DB603G) with dual-supercharges, or with mods to the landing gear Turbo-prop it!
Streamline the gun pod a bit more and fit dual BK-3.7cm's or a single BK-5cm in it.
That's a start for me.......bugga I can see another "project" in the planning......may draw up my ideas if I get a chance!