CM 4228HD built-in balun

[uglydukwling]

My 4228 arrrived this week, ahead of schedule (the dealer had said it would be at least mid-February) so it's time to install it and see how it works.
The problem is that it has a built-in balun for a 75 ohm output, and my pre-amp has a 300 ohm input.
Using a second balun to bring the antenna output back to 300 ohms would introduce unnecessary losses (how serious?)
The balun is rivetted to the phasing wires and the rivets are part of the balun, so I won't be able to remove it without destroying it. I'd rather not do that in case I ever upgrade my pre-amp and need a 75 ohm connection. I suppose baluns are cheap enough that I really shouldn't worry, but this one is neater than one dangling from its wires.
Can I leave the balun in place and by-pass it? I won't be able to connect to exactly the same place on the phasing wires as the balun is connected because the phasing wires are tight against the balun. I thought that it was critical that the length of phasing wire had to be the same on both sides of the connection point, but the lengths are different already so maybe an off-centre connection won't matter. Also, will the presence of the balun have any effect on the antenna with only its input side connected?