Balr14

Is it difficult?
Is it worth it?

C43HeartBoost

Are you asking about the cost of adding an electric motor and battery from an E53 to a c43? I do not really understand your question.

Balr14

I was just interested in what it would take to increase power by the difference between the two models. Apparently, an aftermarket tune would do it. Something like a JB4 with 93 octane seems like what I am after, but I'm guessing.

C43HeartBoost

The E53 makes 429 horsepower and 384 torque, which should not be hard to meet or exceed with a tune or JB4 on a C43.

I know your question was about “power” - but I think performance is perhaps more relevant. The E53 weighs more than the C43, and puts down a 1/4 time around 12.5 to 12.6 which is not much faster than a stock C43 (I have seen a few stock C43 on here post times faster than 12.5, but I believe 12.7-12.8 is average). On a stage one tune or map 2 on JB4 you should see 1/4 times in the 12.1 to 12.4 range - and on a stage 2 tune or more aggressive JB4 map you will normally see 1/4 times in the 11.5 to 11.9 range (many variables here). With upgraded HPFP and LPFP with an e85 blend (or using WMI) you can see low 11s times (I am aware of one user here getting into the high 10s).

Balr14

I should have said I'm looking at a C43 convertible. From what I have read, the convertible is at least 400lbs heavier than the coupe or sedan. 93 octane and E85 is much more common around here than 91 octane. I don't mind buying a tuner, but I'm not interested in other mods unless necessary. I am 79 years old and don't drive much any more. I just like an occasional pull on a freeway entrance. Realistically, there's no place around here you can accelerate for more than about 6 seconds before rear-ending an SUV.

MaverickC43

These cars are crazy fast.
and handle amazing.
If ur not looking for times or to track a tune might be a waste.
get better tires if ur on runflats