Which lowering kit rides the best and will be the most durable. Eibach, sprint, or B&G.
The eibach pro lowers it 1.5 front and back and the eibach sportline lowers 2 front and back.
Sprint is 1.8 up front 1.7 in back.
Then the b&g has 1.75 drop front and back.
I figure the more lowered, the more rough the ride is going to be, so pretty much i'm trying to figure out what is going to be the most durable

 

I have Eibach Sportline springs. Had them on for almost 40k miles with no issues. The struts are getting to where they are due for a change because of mileage, not because they feel worn out. Always upgrade struts when lowering.

 

OK, well i just replaced the struts like 8-10k miles ago. They're straight from daimlerchrysler(wasn't thinking about lowering it at the time), but would they be fine for a while? Or, should I still upgrade them before I lower it?

 

Well,its always best to upgrade to something stiffer.I went with the KYB GR2's which are 15% stiffer then stock and I have had no issues at all. Reccomended is the KYB AGX's which are fully adjustable. They have 4 adjust settings.

 

okay i looked into it and i don't see any agx struts that fit the 6 or 4 cyl....help? And another question, I have a i4 in mine, do the sxt and r/t have the same suspension? oh and yet another....after I replaced my struts up front the ride was more smooth and a little more quiet, but it still seems to hit bumps harder than when I bought the car....might I possibly need new strut bumpers or...what? I also have 3 loose engine mounts, but that shouldn't make any extra noise over bumps, just slight abnormal vibrations, right?

 

Search for the AGX struts under 00-05 Mitsubishi Eclipse. Same chassis. V6 or I4 uses the same suspension. Not sure what could cause it to hit bumps hard.
Bad engine mounts are common, and cost about $100 for upgraded inserts. Bad mounts just add to vibration like you said.