There are some instances where the weight reduction can actually be detrimental to the car's performance, even with proper tuning. It really all depends on the car and the amount of weight reduction used.
^ Tire compound also has a factor on how the removal of weight effects the handling. Hard compound tires tend to loose grip if too much weight is removed. Soft compound generally responds well to less weight. Keep in mind, you can use weight reduction with the ballast system to give your car better balance as well.
In real life, removing weight from a car without performing other modifications usually messes up the car's handling by altering the suspension balance and the weight distribution. None of this happens in GT5.
In real life, removing weight from a car without performing other modifications usually messes up the car's handling by altering the suspension balance and the weight distribution. None of this happens in GT5.
In absolute terms, yes it will be a better, faster car. However, in terms of PP limited racing, less weight also means less hp, and often the lower hp has a bigger negative effect on lap times on many tracks, than the lower weight has a positive effect.
So, if you are not racing in PP limited terms then reduce the weight. If it diminishes the car and you can't fix it, look up a tune for it here and you'll find something that works. Praiano's Garage has about 1,000,000 tunes in it...lol..and there are lots of others.
Or, you can just add the weight back via ballast and be right back where you started, so long as it's less than 200 kgs.
Thanks! Always good to hear! 
