The Liberty side cover mod and steel forks are a cheap and worth while modification that really doesn't affect anything else
I really think you should faceplate third and fourth gear and leave first and second alone for a street box
A good shifter and linkage is the key to clean shifts,for an H-pattern shifter get the Hurst Super Shifter III, for a V-gate go for the Long shifter and fab up your own linkage with heim joints and steel tube shift rods
Gus