Sap Sipper has its merits (mostly making Ferrothorn and Amoonguss/Breloom cry), but Gooey is still amazing (and quite trolly XD). Toxic isn't that good for Goodra, but infestation works wonders since it also traps and you can always have a teammate pop in and set up.I'd say Goodra's best set would probably be a modest/calm special tank set holding leftovers with 140ish Sp. Atk EVs, around 152 Sp. Def EVs, leaving about 216 HP EVs, running dragon pulse and fire blast for decent offenses, along with rest for durability and toxic for eating away at your opponents. I'd definitely say Gooey is his best ability, as along with sticky web, you could just slow your opponents down to a crawl.