What you will need me to tell you is that the car has a tremendous and savage presence in the metal. And that it is quite beautifully made. Walking around the car with Andy Palmer, the Vehicle Line Director for Ultimate Series, is a treat because there is plainly so much going on. From the two-piece windows to the carbon fibre plenum, which can be seen working in the rearview mirror, to the visible door gas struts, it is certainly one of those machines which rewards close inspection - if not a long gaze from 15m away. The fact that no single line goes from front to back without swooping into a vent or intake speaks volumes about the styling sacrifices made at the altar of airflow.
This translates into a power-to-weight ratio of 668hp-per-tonne. And when you've finished staring at that figure, consider that the Senna also develops 590lb ft of torque. All of it dispatched via a dual-shift seven-speed transmission to the rear wheels. There are no hybrid gubbins as there were in the P1 - they were plainly considered too weighty - and while McLaren isn't prepared to discuss performance figures just yet, it has gone into some detail about how the Senna turns all this mechanical energy into potentially outrageous lap times.
Underneath, the car is built on an evolution of the carbon fibre Monocage III architecture which underpins the 720S. Its development occurs in the upper portion and is significant enough for Woking to describe the latest monocoque as the 'strongest' ever built for a road-legal McLaren. As a result, the interior luggage-carrying space in the Senna is reduced to just enough room for two helmets and a race suit (we'll call that, 'the essentials').
Clearly 50mm is a lot for an already low-to-the-ground supercar (even Palmer admits that you'd think twice before deploying it on the notoriously unflat Nordschleife) but then it's meant for the bowling green surfaces of race circuits rather than your local B road. There it will fully indulge the ground-breaking front and rear active aero; from the two aero blades now hidden either side of the nose to the colossal double-element carbon fibre rear wing - all of which constantly adjust to optimise the available downforce and aerodynamic balance.
That's not all. At the back there are 'gurney' flaps ahead of the clamshell's stepped louvres to direct air away from the rear deck and down the side of the car. This leaves an area of low pressure which helps to draw out the heat coming from the radiators and engine bay. Like all McLarens, the exhaust exits the body via the most direct route, but is angled to direct gases away from the rear wing. The vast double diffuser below is created from a single piece of carbon fibre. That glass in the lower portion of the door is there so you can be in no doubt about whether or not you clipped the nearest apex.
In short, it's all about attention to detail. The cockpit is similarly business-like. Stripped out even by McLaren's spartan standards, there's carbon fibre on display everywhere - and while Woking has opted to retain niceties like the infotainment display and a stereo, it has endeavoured to keep clutter to an absolute minimum. The glorious seats (available in two sizes) are only cushioned precisely where they need to be, and can be gently tailored to best fit their new owner.
The car which bears his name is obviously McLaren's tribute to that sentiment. Or at least it will be until Woking gets around to a building a non-road legal GTR version, an option apparently being discussed behind closed doors. Palmer reckons such a development would strip an additional 50-80kg of non-essential kit from the Senna; making it impossible to drive down the public highway - a key criteria for membership to the Ultimate Series - but quicker still at the business of setting lap records. That's a prospect for tomorrow though: today, the Senna is as extreme as McLaren gets.