I replaced the OEM speakers for polks, add 1 pair of 6x9 at the back and a 12" infinity SW. All powered with 3 amps..
I dont love spl, but i like fedelity and this brand really do the job.
I hope this helps.
I'm going to give the same advice that I give to everyone who asks me what speakers "sound good." My ears are not your ears. What sounds good to me, might sound too "tinny" or lack "natural sound." The best, most effective way to see what speakers you like best is to go into a store (several would be better), set the demo head unit's EQ to "Flat" and then give several brands and models a listen with the type of music you enjoy. Be sure to set the demo tuner's head unit to "Flat" though. Some stores tweak that EQ to make the speakers appear to sound better than they actually do.
Your ears are yours and the best recommendation I can give is to use them and trust them.
You don't have to buy the speakers in the store either. Go, have a listen, settle on a brand at least, and seek them out on the internet for a better deal.