need help on shocks+bushings

[onesixthree]

to all the suspension gurus, all four shocks are shot and i just ordered oem rear shocks but i found a cheaper source for bilsteins. im not gonna bother to return the rears but i will be installing bilstein front shocks with them. will it be ok to run different shocks? i assume the bilsteins will be stiffer than oem(sachs?) im also planning to do suspension rebuild with new bushings. front end is starting to clunk and the rear end is all over the place. can you please advise what to look for and what to leave alone. i have a 2002 320 62k milkes driven in nyc roads. i think i hit more potholes than dodging them. lol thanks in advance