Let me start off by stating two things here, well maybe three LOL . I have adressed this topic before and have disagreed with some there who have already responded. I currently am employed by a company that makes antennas for military aircraft. I have disussed this very thing with members of our engineering staff.. That being said this is the way I see this.

1. Running power leads longer then 12" is a bad idea to begin with. The power losses over 12" at the current our airplanes can draw is higher then we think, especially when using 20-22 gauge wire. I can't really throw a number up here because there are just too many variables.

2. By doing this I am going to assume the worse ( because it is the safest thing to do ) I am going to think that you are just connecting flat extensions together. Each connection is a power loss. Now the kicker, the extension still has a signal wire that is unused but does plug directly into the RX. Depending on signal strength, it CAN act as an antenna and transmit the noise directly into the RX. Un-twisted DC power wires can emit an EMF field that gets stronger the more power that flows through said wire.

3. Your rudder and elevator leads are most likely being thrown into the mix as well. Their long leads can pick up on noise. If you have pull pull for the rudder, steel cables and pick up on noise.

4. There are alot of guys who say the " Old School " install of seperating ignition components will claim to have not had any issues by just throwing their stuff in the airplane and I am sure they are being truthful. Last time I had a radio issue was 2006. About the same time I started learning more about how our systems work and what I should be doing differently. IMO that puts us on even ground as far as a track record goes. I like to err on the safe side and advise " Textbook" Installs. I wonder if anyone advising to just thorw the stuff in and don't wory about it would be willing to write out a check should you have an issue and loss of your airplane?