Also curious as to why it's called computer grade, seeing that they are never used in computers.
Anyways, generally they are considered a higher-grade of electroyltic cap, and have very high capitance ratings and low DC resistance and ripple, among other things, such as 40V, 35000 uf.. which you will not see often with standard el. caps.
They're called computer grade because they're used in computers--I work in a room chock full of them. Mind you, we're talking mainframe, not PC. Mainframes are built with much, much higher standards of reliability in mind than PCs (and you can draw your own conclusions about the reliability of networks based on PCs...).
Obviously, computers don't work on 400V rails, but there are 75-100V parts in the tape drives. It's a small matter to scale the voltages upwards to provide parts for other industries where (comparatively) high performance and reliability are valued.
I recapped two Krell KSA250 amps and made an effort to find 105C caps with a recent date code(important!) from a reputable manufacturer(Panasonic). I replaced both the large and small electro's, accepting 85C grade for small caps when necessary. Today's best 105C caps are superior in quality to 40yr old computer grade caps(typically Mallory).
You will probably need to work with several vendors to find the best caps. Schedule 1 month from start.... search... search... shipping... clean... clean... rebuild. I slow charged tested each new cap, mainly out of fear. I used the light bulb on the AC for the first turn on, mainly out of fear. I ran each amp for 24 hrs with a 10 watt output into a junk woofer, mainly out of fear.
Take several pictures and/or video+audio comments as you open the amp.
There are several good websites and UTube videos by top technicians which document best practices and safe cleaning techniques. Mine= Soft brushes + big vacuum + controlled wattage soldering, mainly out of fear.