One last thing. is it just me or do the cables inside the downtube rattle like hell? I'm considering shoving some foam in there to quiet things down.
There is an existing post here about using some foam. But I can't find it...
On my bikes I did cut an insulation tube used for heating pipes.
Cutting a section of about 30mm by 20mm, and about the length of the downtube.
Then remove the fork, and insert it from the headtube down to the bottom bracket.
Canyon have an interesting approach.
They have a hole between the two inserts to screw the bottle cage in the downtube.
And a special plastic hook, grabs the cable suspending them in the middle of the downtube.