Upgrading speakers on 2003 Civic LX

I am planning on upgrading my stock speakers in my 03 Civic shortly.
There's a Soundcity store up by me thats closing due to lack of
business. Everything is currently 50+ percent off. Any recommended
brands of speakers that are good?

Another thing, I am not sure about the stock radio... Does this car
have any preamp I connections I need to worry about. It's been quite a
few years since the last time I installed speakers and an amp to a car.
Over five years since the last time I did it.

So my questions really are:

What brand is decently quality but not high end (i.e. most speakers at
this shop were originally about 150-175 for a pair now they are tagged
75-80 a pair)

How do I wire my amp into the stock radio ( i cant remember if i hook
the battery lead to amp and then wire amp directly to car battery, i
think thats what i did last time, but with a fuse between)

I have an amp from the last installation I had... its a Jensen 300 watt
4 channel amp (about 75 watts a channel peak i guess)


I'm not looking for something thats extremely powerful or expensive but
I want to get some speakers that are better than the stock ones.