My G8 didn't suffer a broken lifter, per SE, but it did have a valve spring break in half, which I initially thought was a collapsed lifter, so I had a full DoD delete and cam installed. I threw as much money as I could afford at the time into that rebuild, including new push rods, springs, oil pump, timing chain and rollers. After 4 years of daily driving, the car developed a tapping on a drive from northern California down to L.A.. That tapping turned to a knocking, then a banging along with a loud squeaking. I thought again it was a lifter failure. I found a great shop in Signal Hill that did the diagnosis and repairs... As it turned out, since I hadn't done the trunion upgrade during the cam replacement, one of the rocker trunions had let go. It was running like total crap, and I thought I was killing it with every minute I HAD to drive it to get off the hiway and onto a parking spot to get it towed to the repair shop. With a trunion kit install and an oil change, it was only a few hundred dollars and it's back to daily driving. BTW... the squeaking noise was coming from the belt drive... we initially thought the wobble of the harmonic balancer would necessitate a balancer replacement, but I changed out an aging tensioner and pulley and the squeak has disappeared. BTW... the valve spring break\cam replacement was at 102k miles, and the latest trunion failure was at 132k miles.