Didn't even realise that the gearstick return spring needed doing :eek: :rolleyes:. Glad you got the heatshield off!
Never had too much of an issue with the rocker cover gasket, its very minor but see how it goes.
You may have to keep re-torquing the manifold to turbo nuts after a few heat cycles, that should help.
Also I've read that V band may be the way to go for connecting pipework such as turbo to downpipe, may be worth a look?