First, thanks for the responses and the kind words, much appreciated. As for the precats on other Nissan models, admittedly I'm not as knowledgable about them as my situation (02-03 2.5L). But, whether it's the proximity to the engine, the precat design or both, these models seem most susceptible to causing catastrophic (non pun intended) engine failure.
Towncivilian, I do remember reading about screws coming loose on some Nissan models and falling into the engine causing engine failure. As I said, I had to have the entire throttle actuator control replaced. The car would hickup ie., cut out for a split second (threw a cel/ses) on the highway, scary. At the time, I told the service writer that this part shouldn't go bad, especially in this short a time. While I didn't buy an extended warranty he apparently agreed with me, because all I paid was the $100 minimum payment. Also, the tech said at the time, that when this first started happening the control was ~$500, but because they had rebuilt/remanufactured so many the cost had come down. That tells you something.
Also, crank angle and/or camshaft position sensors are a problem area on many Nissans, I replaced both this past summer. It can cause the engine to quit or make the engine hard to start, especially when engine is hot and/or when ambient temp is high.
Yes, I do think there is some correlation between a fall off in Nissan quality and the Renault alliance. As spazdog alluded to, I too don't associate Renault with reliability. And while the styling seemed to improve, quality seemed fall off, IMO.
Cost aside, the part that angers me the most, is that as my 1/09 UOA shows, the engine could have been saved with the correct fix. It was preventable, but Nissan chose to let the engines fail. And, while hollowing out the pre cat could be illegal, I could blame no one owning one of these vehicles for using that fix. Frankly, those folks are looking pretty smart to me right now.
Lastly, I do believe all makes can have their issues, and didn't want this to turn foreign v domestic or make v make, part of the reason no specifics about my new ride on this thread. Hope it won't go that way. Thanks.