I just received my P85+ having sold my previous P85. I'm a M5 fan so I tend to like a firmer ride and much more feedback from the road. I had several conversations with both Tesla Engineering and other knowledgable people in the suspension design community prior to the + package coming out as I was absolutely certain I had "firm up" the rear of my P85. Once the Plus package was announced, that education process turned to deciding on the path; do I retro fit my car or go for the production Plus? Obviously, I took the advice of Tesla Engineering and went the factory Plus path. I am VERY happy I took that course but then my tastes tend to deviate from the norm. That very idea got me thinking. If I were not so far to the handling and feel side I think the retro fit option would have been perfect provided it was implimented in a certain way. I would start by installing all the + rear suspension arms (lower a-arm, upper link, torque link and toe link). If you have 21s like I did, I would change to Pilots. If you do not and prefer a smoother ride, I would simply leave the tires alone. I would not go for the mandatory staggered size tires and wheels. They do provide some oversteer margin but, in my case, I am comfortable without that added margin. If you find you are not, you could always make the decision to purchase Teslas package or aftermarket wheels/tires with a similar stagger in width. I would not be concerned about the shocks or the sway bars. The production + damping has been stiffened but I do not think this is core to improving MS' handling and you do pay a penalty in ride comfort. Both the benifit and penalty are small but they are real. This is a comment purly from my gut as I have not driven the exact same car back to back with and without the damper modifications. In short, it is a feeling and not an absolute. I feel the same about the sway bars but even stronger about the negative impact they have on ride quality. One of the engineers I spoke with (Tesla, I believe) went into great detail on how sway bars transfer road irregularities from one wheel across the car to the other. This became abundantly clear to me on my drive this morning when I went across a small construction zone. The car yanks from side to side in a rocking fashion when one of the front wheels has to deal with a pot hole or other imperfection at low speed. The engineer called it head snatch and I see why. Again, I prefer a stiff car and I am perfectly happy with this side affect. For most, I think you will find it the single most imposing element of the + package (or at least second to road noise). That is my 2 cents worth and a lot of the above is based on gut feeling only so please consider it simply one person's opinion.