OK, here we go. I didn't have an '06 CL55 in the shop today so I used an '07 SL55 for the look-up instead. I think we'll be in the ballpark. I did have an '06 CL500 though.

The AMG Kompressor engine is only available new. No re-man's or fitted blocks to be had. The list price is $77,372.00

The standard M113 in the CL500 can be had new for $42,642.00. A re-man is available for $14,650.

According to my calculation, it costs $181.83 per/HP more for the V8 Kompressor motor.

I hope this helps.

I suspect that the difference in insurance premium has something to do with the difference in horse-power.