In the pack, balance has been restored to the loose forward trio, with the combative Kane Thompson returning to No 8 and Liam Messam occupying the blindside, where he has done his best work this season.
Tanerau Latimer gets the nod over young Sam Cane for the No 7 jersey and Hika Elliot wins a start over the industrious Mahonri Schwalger.
"We would have started Hika over Mo [Schwalger] against the Brumbies, but he got injured at training that week. They're both very good players and Mo got a head knock in the 79th minute against the Brumbies so it's a chance to freshen him up and give Hika some serious game time," Rennie said. "Lats has been our best performer in the seven jersey. We're really happy with his form and he's one of our leaders."
The Waratahs have been a difficult opponent for the Chiefs of late, with their last meeting in Hamilton a 19-46 embarrassment for the home side.
Given their respective starts to 2012, the Chiefs will be favourites, although the visitors have been hard to get a read on.
They were impressive for much of their opener against the defending champion Reds, before coughing up victory with a poor final 30 seconds. Last weekend they reversed that scenario against a strong Sharks side.
In between, they have dismantled the Rebels, run the Highlanders to the final hooter indoors at Dunedin and been booed off the Sydney Football Stadium after losing to the lowly Force.
Roller-coaster doesn't come close to describing their season.
"They would have been disappointed with their performance against the Force and their attitude was outstanding against the Sharks," Rennie said. "It just highlights that in this competition you only need to be down a couple of cogs and you can be rolled by anyone."
Rennie is up against another head coach rookie in Michael Foley. He is well aware of the threats the Chiefs pose. "They've always been a side able to spread the ball, they've certainly got pace out wide, and in Sonny Bill Williams they have another dimension in attack," Foley said.