In terms of the original question of this thread, we've gotten way off topic. But what we can say is that adding little swirlies (of whatever kind) to a cowl with the wrong diameter and length isn't going to do much of anything to make the model seem more scale. Painting stripes on a horse doesn't make it a tiger.

So here are the BIG changes that might actually make a difference:

1. Full flying rudder and elevator (at scale size or at most a 10% enlargement)
2. Scale length and diameter for the cowl (which will require an inset firewall)
3. Stick-built rather than slab fuse sides (and since you're making this change and also using full flying rudder and elevator, you might as well make the fuse scale)
4. Put the wing panels on wing tubes (so that you can have a real cockpit).

Of course, if you do all this, you'll find there's not a lot of reason to have started with the BUSA kit to begin with. If you want a reasonable scale model, it's ultimately more economical to start with the AerodromeRC kit...which while it costs a bit more than the BUSA kit, you'll actually end up using the parts. And for those of you who care. it's also made right there in the Ol' US of A.