Rudder pull-up lines! I just did those, lots better than the original bungees.
Maybe put in sideways loading dagger board bungees in place of the fore-aft loading original set up. This to relieve the strain (and particularly the wear) on the aft end of the daggerboard trunks.
Personally I wouldn't bother putting the jib cables under the tramp, though it might help cut down on the mess I get if I leave the jib flogging for a couple of seconds...
Some people remove the center bar. Guess it's just preference, but it never gets in my way and gives the tramp a nice and tight feel.
I'm thinking about putting in a better traveler system though... That way I could get the main on center without flattening it too much. This is just for light to medium winds. Maybe next year though..
Regards, Dennis