When I was looking at E420's everyone said that the caps and rotors should be changed every 60k. You will notice a performance loss if they get dirty. The contacts inside the caps get carboned up over time.

Now onto oil timeing chain wear depends on how often the oil was changed. If it wasn't then their will be more wear. Also a few techs on this site has shown that Mobil 1 will more or less eleminta timeing chain wear or get it down to less then 1 degree per 100k miles.

Frankly their is no reason your car should not run as good, or be as fast as when it came out of the factory. If you want to make it faster then a 5.0 is one way to go but call a few tuners first. You might be able to get more power for less money by playing with your current engine.

btw getting rid of the cats a new car is a wast of time. They don't restrict exhuast much and you will probably lose some power down low. Not to mention your check engine light will always be on.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200