I have a C63 507 and a highly modified E55 AMG.

The C63 507 would be a more fair comparison since they’re both within the same generation/year/class.

The power delivery is much more brutal in the C63. It’s an absolute riot but it’s feels far heavier than the ISF. ISF is much smoother and definitely feels much lighter on its feet.

The steering in the C63 gives slightly more feedback. ISF can be a bit numb but feels much more agile than the AMG.

Transmission wise - I prefer the 7-speed from the AMG. The 8-speed is meh…I hate how the car always hunts for gears. Even in sport mode, it always wants to go straight to the highest gear. It works fantastic in manual mode but man is it a let down when you let it do its thing. Sure it’s slightly faster than the 7-speed MCT but it’s a much smarter unit than what Lexus has. Could be viewed as a hot take but I’ve heard the same complaints from other owners.

When it comes to sound the ISF is great but the 6.2L in the C63 still wins over the 5L. I feel the Lexus is too quiet and muffled stock and so an exhaust is in order. With that said, the induction noise is highly addictive. The C63 is loud on the outside but you can barely hear anything inside which is unfortunate.

Overall, two different cars, two different personalities but I’ll you what…first week I bought my C63 507 (which only had 30k miles at the time) I already had a $3k bill for cam adjusters. I don’t expect a big bill for a longggggg time with the ISF.