Steve Huntley at Great Northern Sound would be a great guy to talk to about that amp. They are factory authorized ARC service to get it back up to speed(the power supply caps may be about ready to need to be replaced if nothing else)and they do high quality custom mods like you are asking about on ARC gear. You would only need to ship it once that way. It won't be cheap, but that's a great amp and worth the cost and effort.
As far as speakers I worked for an ARC dealer that had one of these and it will drive about any speaker you like the sound of with a sensitivity from about 86db and up depending on the size of your room and how loud you like to listen. We had it hooked up to some real power hog Maggies. If it can make them sing anything else is a breeze. If you have a bog room or listen loud or both go for speakers with a few db higher sensitivity figure say 88, or 89db and up. This isn't just a random suggestion. That amp is a jem and can drive damn near any speaker you can hook up to it and sound fantastic. Ask Steve when you call him. He was an ARC design tech. He knows that amp inside and out. With new electrolytics in the supply, a real power cord and some modern coupling caps(I hear that Steve likes the Cardas cap)that thing will be a killer!
