What are everyone's thoughts regarding chassis strengthening? Would you say that your Skyline already is perfect from factory meaning its not too stiff that road use is unbearable yet able to handle any extra power not to mention extreme driving? By that I mean it absorbs the forces acting against it without flexing, at least not noticeably. We see advertisements for all types of products from chassis foam to all types of bars. Have any of you installed any of these products in your Skyline? And if so, what made you do it? What difference has that product made to the car both in terms of handling as well as comfort? Do you regret that decision or was it the best thing you've ever done? Personally, I'm not against chassis strengthening but there are certain products or modifications I'd probably never do. One of which is the use of chassis foam which is injected into various points and then expands and hardens within the hollow points of the structure. I believe the chassis, designed by engineers, needs to flex and the flexing occurs at such minute levels we definitely don't know its happening. But once you introduce this rigidity where its not engineered to be, how safe is that really? Take the example of the human spine. It definitely isn't straight, and the reason why its curved is to allow the proper distribution of weight, give us flexibility and mobility yet allowing the skeleton to support the weight of the body while protecting the spinal cord and whatever wiring harnesses inside. So its very much like a chassis isn't it? What happens when the spine is straight? Well it then becomes inflexible and weight is therefore wrongly distributed, placing strain on the lower back and even back of the thighs. Don't worry Prof Nain, this isn't Google'd or Wiki'd but rather based on my own spine. :proud: So let us now discuss chassis strengthening and hopefully add more information so that in future, this forum can become a knowledge base for all things Skyline related. Disclaimer: For the sake of this discussion, chassis strengthening will encompass both modifications made to strengthen the chassis as well as body of the car with the goal of improving handling by introducing rigidity into the overall structure of the car.