Stock Leaf Spring Replacement HELP!

It's been a while since the thread was updated last time. I need your TACOMA gurus' help.
I have 04 Prerunner extended cab 3.4L. 180Kmiles on it. When it is lifted in the air the driver's side leaf spring is sagging about 1.5 inch lower than left side. I don't think it is normal. I also feel the driver's rear leans a lot when it is turning right on freeway bypass.
I think I need to replace them. I gave dealerships VIN 5TESN92N44Z428926, and they all fave me all different parts numbers.
48210-04210
48210-04310
48210-04330
48220-04130
48210-04340
48220-04100
48220-04130
I am very super confused as to which ones to buy. I found the part number 48210-04330 won passenger side and 48220-04130 on drivers side. One dealers says they are not correct parts.
I don't know either the dealer has no idea what they are talking about or the original owner replaced with wrong part (I hardly believe this is the case since it was a fleet corporate truck. I think they are the original springs came with the truck) Please someone provide me with guidance.

 

http://www.generalspringkc.com


Probably cheaper as well.

 

Take the shocks off and lift truck. I bet the passenger side one is limiting droop.


Drivers side is supposed to have a little more arc to prevent the taco lean. How do the they sit with the truck on the ground?

 

Id go with the generals as well, dont mess with another set of oem springs...

 

It is lower about 1 inch on driver side when it is on ground. I looked others thread these are my options for stock height. Factory Toyota leaf springs $400~550, Wheelers spring $450 and Generals spring $120~170 each.
I do ZERO off roading. This is my commute truck. The most important thing for me is reliability. I want springs last for long time. Are General and Wheelers springs built better than factory springs?

 

Yes, much better.

 

So Generals's springs are much cheaper than factory spring, less than a half, and better built quality. I usually go by with a mentality "you get what you pay for." I guess it is different in this case.