Yes it seems to make a difference, they are easy to replace (perfect time is when doing an oil change) even the one in bank 2 is easy with the right tool...
Just make sure you submerge them in some oil and pump them full and then shove them in
Autopartsway.ca had a good price on them a while ago (I think I paid like $340 for all three) I did a tension test on the old ones and new ones and there was quite a difference....
H