Car: 2006 Chrysler SRT8
Join Date: Apr 2007
Thanked 1,983 Times in 1,792 Posts
My responses are:
1. The LC2i will be a good addition, as will the Alpine. The Alpines have a bit of a higher noise floor than the JL amps so what I'd do is listen to the speakers you select with both amps and make your decision from there. When you go with an amp, match the ohms put out by the amp to what the speaker is rated at. Add a little wattage RMS on the amp specs to what the speaker is rated at to give you some head room. I have the JL XD 300 in my truck pushing a Hertz HSK 165 2-way system. It sounds pretty good. I also have an Alpine MRP-M500 sub amp driving a 10" Alpine Type S sub. It works for the truck pretty well.
2. I'd do the same thing with the woofer. Find a woofer & amplifier combo that works together. Listen to a few. JL makes some nice amps so matching an amp (ohms & wattage) to the sub is the last thing you'll have to do. Give yourself some headroom (more RMS wattage from the amp than the speaker requires) so you aren't stressing the amp just to meet the speaker's needs.
3. A good 5 channel amp saves room and, in my case, works pretty well. The same conditions apply as mentioned above. You won't realize the potential of your amplifier upgrade until you do something with the speakers.
4. Again, you won't realize full benefit of your amplifier upgrade until you replace the tweeters. Just be advised that most will sound a bit "bright" bouncing off the glass. I will qualify that statement saying that they sound bright, sometimes harsh, to me when they bounce off the glass.