[Watsey]

So here are my thoughts as the unbiased independent in last night's back-to-back road test. It was very interesting and thanks Guy for the chance to drive your car.

Terry and Guy have covered things well, so I'll try and add what I feel are the key differentiators which have really helped with my decision-making.

Focussing on ride and handling, i.e leaving other things like power and brakes to one side, my starting point is the base car (in my case F31 330D sD). There are several problems with the stock build :

- RFTs are so hard that the ride quality is nadgety, they don't key into the road surface so they can scrabble for grip, straight line traction is compromised on wet/damp roads, and there's a horrible combination of understeer and weight through the bends.
- Spring rates and dampers (adaptive on mine) are not working in harmony, resulting in wallow/floating (bump is 'OK', but rebound is very poor especially in Comfort), and mid-corner bumps can result in very unsettling barrel-roll. Rapid direction changes tend to easily expose the shortcomings.
- The overall capability of the suspension set-up has a fairly limited performance envelope and on UK A/B roads it can be more a case of blind faith, rather than confidence that keeps you going.

The stock package is very compromised, to the extent that it really spoils my enjoyment of the car.

I drove Terry's car a few weeks ago and the combination of Birds' ARBs, ACS springs and MPSS makes a significant difference in ride quality, cornering neutrality, and roll. The three of us were talking before heading home last night and we all agree that the ARBs are helping the adaptive dampers massively. The ride is firm, the benefit of having adaptive dampers is retained, understeer is hugely reduced (also helped by the excellent Michelin Pilot Super Sports), and the car feels composed. The car can now be hustled down a bumpy twisty road, rather than wrestled. IMO the suspension will tackle British roads, with good control (driver limitations excepted...), up to, say, three figures.

For the majority of drivers who want to improve their car but still retain the comfort of a daily driver, this will tick most of the boxes.

On to Guy's ACS RS setup. No doubt about it, the ride is very firm around town and up to low-moderate speeds (say 50-70 mph) you feel every irregularity in the road surface BUT the suspension doesn't crash; it's busy, but not unpleasant. The dampers do an outstanding job of controlling body movement at speed, and handle primary and secondary inputs with aplomb. The car is absolutely tied-down to the road surface and there is a sense of 'immediacy' - no float, no wallow; you can feel exactly what's going on. Turn-in and neutrality are spot-on. Very impressive.

To me, and I'm no racing driver, the capability of the suspension felt very linear. From 50-70 mph the car really comes alive and, leaving aside the safety and moral aspects of big speeds on public roads, the cross-country capability could embarrass full M-cars; no doubt.

The more I drove Guy's car the more I liked it. The ride is very focussed, uncompromising, and if it was just me in the car I would be very tempted with the ACS RS setup; the additional confidence when one is 'on it' is worth having. However, I think it's just that bit too firm as an 'all day every day' car, and in reality I'd probably get an earful of complaints from my wife and kids when we all travel together, especially rattling along Devon roads where we visit regularly.

My car is going into Birds' next week for ARBs, ACS springs, and MPSS. This package makes such a positive difference to the car's capabilities that it is the sensible compromise (and actually not that big a compromise; I don't track my car) and won't cause any disappointment. It's also better value for money. Having driven each setup, they are similarly matched at sensible speeds and it's clear that a relatively modest amount of money can transform the ride, composure and capability - these are meant to be driver's cars, not boats. There will be moments, when I'm having a cracking drive on my own, when I will remember driving the RS setup and I'll think "what if...?", but for >90% of the time the car will still bring a smile to my face.

When I've had the work done, we must meet-up again and see how the sD and xD setups compare, and see how much the sD gives away in terms of traction versus what it gains in terms of steering feel and turn-in.

Bring it on !