I have a 1993 legacy and I put 98 outback struts in the rear. I haven't replaced the front ones yet but when I turn right there is a clunk from the rear. I am assuming its is either my rear differential binding a little or the angle of my cv axles. Will the clunk go away if I replace the front struts with struts from a 98 outback? all input welcome

 

You need to find the source of the noise.  Changing the length of the strut put your CV joints in a new spot, but if they were in good condition that should be OK.

Did you make sure the top strut mount was tight?

I've swapped struts where you need a thick washer on top of the strut mount to take up the added length of the top strut mount.  Otherwise the nut runs out of threads and you still have movement of the top strut mount plate.

To clarify what Imdew said, the non-threaded part of the Outback strut rod where it goes through the strut cap is longer. So when you run the nut down on the strut, it jams on the threads before it clamps the older legacy style strut cap. That lets the strut rod clunk around in the strut cap. If you take the nut off the strut and put a washer under it, it can then clamp tight. You can do this without pulling the struts out of the car, just don't bounce the suspension up and down while you have the nut removed because you risk popping the strut out of the cap and turning it into a PITA job.