Let me help.
1) strut bearing is same for 03-08. They all work.
2) Part numbers differs from I believe 03-05 to 06-08.
3) The change is a metal bearing in 03-05 then infiniti went with a plastic bearing. The metal bearing is 2x a big but the plastic one works in 03-05.
4) the metal bearing went up in price from around $15 a few years ago to $44.95 as you said. The plastic ones are $15.
5) It is still up in the air which one lasts longer, metal or plastic. The metal, you can HEAR it failing, as it's grinding metal. The plastic, not really -- so I guess you can't really tell if it's failed unless someone corrects me. And as far as the forum goes, I haven't heard of one plastic one failing.
Having both in my hands and seeing the metal vs plastic, I'd rather have the metal ones. But the metal ones do fail, but all bearing fail.
6) I've heard rumors the change from metal to plastic is either cost (plastic is cheaper) or the fact that so many metal ones have failed. Who knows, but the plastic one is used on many cars from like altimas to muranos to infinitis.
Long story short, you could have saved $60 using the plastic ones. The tech is just doing his job and telling you what is in his computer, he just doesn't have the experience to know you are 100% fine with the plastic one for the "07".
I ordered mine last week for my 04 and a couple of days later the dude from infinitipartsusa.com calls me saying that I ordered the wrong part because it did not match the vin number and there was difference in price.
I ordered by mistake the bearings for an 07 for $15 each and for the 04 is $44.95 each. So I had to pay $60 on top of the $30 i had previously paid.
I just got the parts yesterday I don't know what's the big difference with these bearings. ????
