One of my favourites. You don't need the free dlc (it's basically just a time trial level), but you can get the extra 3 stars (depends on how good you are) for the 'Superstar' trophy ( obtaining all in all 90 stars in time trials), which can be pretty helpful if you have issues with some levels
(you can get overall 99 stars iirc). It's not a cake walk, but it's definitely manageable with some help -> e.g. youtube.
If it wasn't for you the first time around then don't force yourself, but since it's been 'years' I guess you could def. try again (also for 4€, why not ¯\_(ツ)_/¯).