If you are dying to get the entire Shimmering Gold Palace workshop set, but don't have nearly as many stars to do this (8000 total), there is a trick that I recently discovered that allows you to play online levels over and over and still get stars for them:
1) Start up the game and go to Community.
2) Select the level(s) you want to play.
3) After playing as many levels you like and earning stars, turn off the system completely. (I don't know if you will have the same outcome if you just exit out of the game and restart it on the home menu, but you can experiment with that if you want)
4) Now restart the system and the game, and go to Community. You will notice that all of the levels you have played no longer have the green check mark on them, meaning you can earn stars on those levels again.
5) Finally, rinse and repeat everything for as long as you want, and you will get all of the Shimmering Gold Palace workshop parts including gold mini mario, the SGP theme, and the gold pipes and girders in no time.