For amps - I recommend the following:
Hifonics Zeus Series
Phoenix Gold Octane 8.0:4/Octane R Series (same one I got)
Precision Power PCX Series
Soundstream Picasso Series
I have personally installed all the above and highly recommend them. If you rather spend a little more, you can buy the bigger versions of all those amps. Best deal, IMO, is the Phoenix. Yeah, they kinda look ricey (ha!) but they put out a deal of power.
For front speakers:
Diamond Audio M Series
Infinity 605CS/Reference series (if i remember correctly it was)
CDT cL61, 6.5" (same as I got, other from this company very expensive)
Kicker K Series
Crystal CP series
MB quart PSD series (a litle expensive, but sounds good)
At this time, best for the money is the CDT. I used to install them all the time, but stayed away from them because of expense. All the others listed are awesome for the money. Best overall sound did come from the Crystal's. Ive noticed they have dropped in price a bit.
Best sites to check out:
www.sounddomain.com
www.nexxon.com
www.millionbuy.com
www.ikesound.com
www.thezeb.com
Most of the amps listed are about $250 avg. The front components are $125~200 avg. Rears are your choice. You could go components, but there is no stock tweeter location. Ive opted for coxials in the rear. If thats your plan, they are $60~125 for a good set. Prices are based on 6.5".. so they will be cheaper if you go with 5 1/4".
You will spend about $435~575 in equipment alone. That leaves about $125~265 for install.