Completely out of curiousity here and just bored-
Assuming both cars were driven by same owner since new, taken care of roughly the same, abused/pampered roughly the same, etc......
Also this has nothing to do w my willingness to purchase either (I already have one)- informational purposes only.......

What would be a more reliable car to own in the long run, specifically regarding maintenance issues/repair costs/frequency of problems?

I'm also not talking about 14 year old cars here, we'll say up to maybe 125k miles and/or 8 years old.

1. 2006 E55 - More parts to fail - supercharger, intercooler, belts, heat exchanger, etc.....

2. 2007 E63 - Less "moving/working" parts per se, though the high compression motor I'm sure has more stress on valves, pistons, etc, whereas 55k motor MAY be driven under less stress more often.

SO.... assuming variables are the same, is it a toss up?

Thanks for the discussion gents!

Well some say the reason amg engineers went to a na motors was due to some issue with the sc motor. For example sc clutch problem etc ect.
Also in term of warranty the na 63 motor maybe cheaper to maintain for mb.
Get the 07 63 atleat you get an additional year of factory warranty.
On the other hand if you want to mod then to sc motor has more potential.

This is a completely speculative question that has no realistic answer. They are very similar with different engines and transmissions. There already are E55s with 125k miles, and not any E63s. Who knows.

-m

I already have one of these cars, not looking to trade anytime soon, and modding is not a factor.
I fully realized originally and agree with Marcus - Very speculative.......

I would be interested in more opinions

Heat was always the weak link in our 55's which just just can't be good long term.

Like said above though, already seeing them over 100k so those German sure know how to over engineer!

Another good point is that 55 engines and parts are really coming down in price. Blowers are down from 10K to 4kish (all refurbs) and used motors are popping up under 10K.

Can't imagine what a set of heads or bottom end is for the 63's being so new.

Any furthur input from others?

Either motor should last at least 200K with proper maintenance and minimal abuse. It's a combination of good initial tolerances, and an extremely over-engineered oiling system pumping a good synthetic. That's not to say there won't be failures of accessory devices or other parts of the car (I'll bet the transmission dies long before the motor in either car), but if you can't get 150K+ out of these motors, you must be trashing them.