The only disciplinary action needed when these two heavyweights tussle will be from the bank manager, because it's now a proper bust-up: BMW M6, meet the brand-new Mercedes Benz SL63 AMG.
Mercedes has revealed its rather delectable new SL packing the full complement of AMG's modern know-how. As such, it is the latest in a long line of new Mercs (CL63, CLS63, E63, S63) to get the 5.5-litre twin turbo V8 petrol engine, rather than the 6.2-litre naturally aspirated monster still lurking underneath the bonnet of the AMG C-Class Coupe.
If you opt for a regular SL63, you'll benefit from 537bhp and 590lb ft of torque, a 0-62mph time of 4.3 seconds and a limited top speed of 155mph. Opt for the AMG Performance Pack, and that power jumps to 564bhp, 664 torques, a 0-62mph time of 4.2 seconds and a limited top speed of 186mph. Clearly, this latter figure is a little bit more than the new, 552bhp BMW M6, and thus the one you want.
That 5.5-litre V8 is mounted in an all-aluminium bodyshell - with a carbon fibre composite boot lid bonded to the plastic outer shell - that helps shave 125kg of weight from the outgoing SL: the new one weighs 1,845kg.
And it's also getting a reworked version of Merc's active body control which, as you're probably aware, gets Sport and Comfort modes, together with more negative camber all round and fully revised elastokinematics.
AMG's Speedshift seven-shift auto ‘box is clearly crying out for some punishment, what with its ‘S', ‘S+' and ‘M' modes, while you'll have hours of fun with the ‘Race Start' function. The standard fit brakes measure 390mm up front and 360mm at the back (although you can spec the SLS's ceramic compounds if you want more stomach-shrivelling excess) and sit inside 19in light-alloy AMG wheels.
The drop-top comes in painted, glass or panoramic variety, and inside it gets stuff inspired by the SLS: think jet-engine air vents and AMG sports seats. There's a range of CAPITALISED stuff such as Attention Assist, Magic Vision Control, Neck Pro head restraints and such, along with a dizzying array of options including that fabulous ‘Airscarf" neck heater and high-end sound system.
It'll go on sale in the UK later this summer with prices to be confirmed closer to its launch time. We're guessing somewhere in the region of £100k. Though whether it'll sell more than the old supercharged SL 55 AMG (which Jeremy used to own) remains to be seen; it remains the biggest selling AMG model to date, with 21,500 sold between 2001 and 2007.
Reckon this will shift more? And would you choose this, the M6 or Jag XKR-S?