I haven't considered doing this bearing change myself. You don't mention if the router is fairly new and lightly used or old and has seen a hard life.
Some things to consider though.
1. Is the router housing plastic? The run out could be due to flexing of the plastic under side loading. The outer bearing race may not be fitting the plastic housing snugly enough to prevent movement. Better grade bearings won't solve anything on these routers.
2. Is the router housing cast and/or machined aluminum? If the bearing is a drop in fit instead of pressed in fit, putting in better grade bearings won't solve anything.
The only way to know if installing abec 7 bearings will help is to spend the money and try it. Personally, my thoughts is that if the router is old and has run out problems, it is better to buy a new high quality router than to spend money on a potentially dead end pursuit. Use the old router for noncritical woodworking tasks.
CarveOne
CarveOne
http://www.carveonecncwoodcraft.com