Shuttle tips / mods

[trillian]

I have just acquired two Shuttles. One is a plus model and the other looks very old, like perhaps one of the original versions.

They are both second-hand, have been flown etc. but still have all stock parts.

I am going to go through them for the general stuff like thread-locking the usual bolts etc.

Are there any particular things that should be replaced / modded on shuttles ? Or things I should lookout for etc?

Thanks,
trillian