WRT54g2 and comcast modem, internet dropouts, losing my mind.

Question

Title of the post sums it up. I've literally spent hours and hours on the phone with linksys tech support. I've replaced the modem once and the problem is identical. 
Basically, I get everything setup and it works fine for a period of time, usually a few days. Then, internet gets really slow before it stops working altogether. 
When I lose internet connection however my home network is still functioning. My computers still talk to each other and I can usually still stream content to my PS3. Even my utorrent downloads will continue seeding and downloading. 
When it internet stops working I power cycle the router and it works again. But every time I do that the period of time that it functions properly gets shorter and shorter, to the point where I will power cycle it and within 5 minutes I lose internet. 
Firmware is up to date, 1.5.01. Wireless network is secured. I do not experience any dropouts when the either computer is wired directly to the modem. 
I have a W7 laptop on wireless, wired W7 desktop, and a wireless PS3 on the network. And recently I began sharing my wireless with my neighbor. But I've had issues long before that. 
After some research, I came across this thread. 
http://homecommunity.cisco.com/t5/Wireless-Routers/I-need-to-reconfigure-my-WRT54G2-to-work-with-Com...
Basically setting the the router ip to 192.168.2.1 instead of 1.1 and enabling mac address clone. 
This actually helped and I thought my internet woes were over. But at the time I was in between desktop PCs (building one to replace my old Dell). 
After a couple days of my new desktop on the network my old problems began again. Could utorrent be causing any issue because I notice it seems to get worse when my desktop is downloading, or maybe not it just seems that way. 
There have been times where the computer gave an ip address conflict message. I've tried static ip but have not been able to get that to work probably due to something I've been missing in the process. I'd prefer not to have to resort to static ip because I take my laptop to work and for travel and would prefer not to have be going back and forth on my settings. And I would like guests to be able to come over with their laptop and just quickly log on and not have to change their ip. 
So I'm at a loss, not sure what else to try. This is also the 2nd brand of modem I tried, the first was a dlink that I just returned right away because I thought it was faulty. 
Any thoughts or suggestions would be very much appreciated. 
Thanks. 

Answer 1

MTU is the Maximum Transmission Unit. It specifies the largest packet size permitted for Internet transmission. Keep the default setting, Auto, to have the Router select the best MTU for your Internet connection. To specify a MTU size, select Manual, and enter the value desired (default is 1400).  You should leave this value in the 1200 to 1500 range.
The default value is 100. Enter a value between 1 and 65,535 milliseconds. The Beacon Interval value indicates the frequency interval of the beacon. A beacon is a packet broadcast by the Router to synchronize the wireless network.
This value should remain at its default setting of 2347. The range is 0-2347 bytes.
<script type="text/javascript">// Capture(hwireless.phase11) // </script> Should you encounter inconsistent data flow, only minor modifications are recommended. If a network packet is smaller than the preset RTS threshold size, the RTS/CTS mechanism will not be enabled. The Router sends Request to Send (RTS) frames to a particular receiving station and negotiates the sending of a data frame. After receiving an RTS, the wireless station responds with a Clear to Send (CTS) frame to acknowledge the right to begin transmission.
This value should remain at its default setting of 2346. The range is 256-2346 bytes. It specifies the maximum size for a packet before data is fragmented into multiple packets. If you experience a high packet error rate, you may slightly increase the Fragmentation Threshold. Setting the Fragmentation Threshold too low may result in poor network performance. Only minor modifications of this value are recommended.