I have a Linksys wrt54gs v6 speedbooster router w/DD-WRT hacked firmware installed.
Despite speedbooster technology being the so-called selling point of these routers, which were generally a flop, speedbooster routers are known for their extended working ranges compared to other wireless-g routers, and they are also known as some of the fastest mixed-mode (G/

routers available, working at speed of around 24-25mbps on a mixed mode network. In comparison, wireless-g only networks only average 24-27 mbps. So, there is virtually no speed loss in mixed mode compared to all of the others which take a huge performance drop.
In order to take advantage of speedbooster technology, all products on the network have to be speedbooster products, and linksys is the only company that makes them. This is why the technology failed.
The wrt54gs comes standard as an access point and router, but with DD-WRT firmware, it has a huge list of features. It turns a $60 router in to a $600 router. My two favorite features would be the adjustable transmit power and the ability to go in to repeater mode, or even an enhanced repeater/bridge mode, where it actually acts as both a bridge and repeater at the same time.
Most routers have somewhere around a 40mw transmit power cap, and the power cap is sometimes built into the factory firmware. Many routers have a maximum of 80, even with hacked firmware, but this particular model has a 250mw cap in the hacked firmware, which is 5 or 6 times more power than most other routers.
What exactly does the transmittable power do? It sends the signal out further or can even make an unstable signal more stable. Remember, in wireless networking, the speed you get has a lot to do with the signal from point A to point B. If you have a weak signal, the speed is automatically adjusted lower. You could be getting as little as a 1 or 2mbps connection, when you should be getting an 18-27mbps connection.
I can't guarantee you'll see that kind of improvements, because a bad network connection can be a combination of many things, such as distance, interference, objects blocking the line of site like walls, buildings, or trees, etc. I've spent probably over $1000 building a network of wifi connections through bridges, repeaters, and expensive antenna systems, including the usage of power hacks. I've seen the wifi signal increase by at least two bars (out of 5 I believe) going from 40mw to 80mw alone on my other repeaters.
*WARNING* Only use in a well ventilated area, as the afterburner (Speedbooster) technology and higher MW transmit power can cause the router to heat up. It has been reported that some routers become unstable if they get too hot, and it's even possible that the router could burn up. After all, this router is basically a 200mhz pc with no cooling fan in it. Putting the power output at 250mw would be like overclocking it! Only adjust the power until you get a stable signal - don't be greedy, or it could cost you in decreased performance due to the power output being too high for other network components that are close to it. It would be something like distortion. *WARNING*
I'm very tempted to keep this for myself, but I really don't need it. I'm putting this up for sale for today only for the GDG members only at $37 shipped anywhere in the USA. It comes with the power adapter.