The things I see as parts pack winners are definitely tire packs. The only cost is packaging and the cost of a run ofwheels and tires.
 
	The headlights sound like a winner.
 
	Another possiblity would be traditional street rod parts. Quick changes, dropped axles, etc. 
 
	The losers would be custom parts and uphostery kits.
 
	Just don't see interior materials as there are better ways to do it. Just look in all the projects here and I doubt you'll find an uphostered interior. Same as parts packs how many projects do you see using the old style custom parts. Second the old kits were not really laid out to be able to run them as seperate parts packs.