Whatta you mean by "higher" package. More performance, more price, more options?
RS was the more highly optioned package. SS was the higher performance package. RS/SS would be the best combo of both. Z28 was an entirely seperate entity on 1st gens and while a good all around performer, was not the highest power option out there. ZL1 were so limited in their availability they were out of reach for most buyers, but they were probably the highest priced of all options.