Some of what those tweaks do are good and bad. Good in that you ought to get a more stable latency, particularly for international connections. Bad in that it will result in, usually, greater CPU overhead (even if it states in some cases that it'll *reduce* cpu overhead), by causing a greater amount of packet traffic to occur.
As another side-effect, because your packet traffic is increased, so is your bandwidth utilization. For some high-bandwidth games such as Bad Company 2, this is bad if your connection isn't fast enough to handle the extra traffic; nevermind your cap. They can also have adverse effects on Torrenting, potentially flooding your router if it is responsible for the PPPoE session if you have too many connections open at once.
It can also have adverse effects on streaming services such as Youtube, particularly at higher definition settings, due to the way they try and optimize streaming for the protocol; your connection is basically fighting with their server asking for more before the server wants to give it to your computer, resulting in more pauses/slowdowns during streaming as the server flips your PC the bird.
So ultimately, good and bad for gaming, bad for streaming, bad for torrenting. Has no worth-while effect for local/international public gaming unless you're really competitive, and has mixed results for international games such as WoW, Guild Wars and EVE-Online.
