well, i guess i'll play devils advocate since no one else will. 
im curious as to the content of the thread you read this in.
was the OP having an issue with RF getting into his vehicles electrical system?
was he having an SWR issue?
there are other reasons to upgrade to LMR240 besides the loss factor.
the shielding on LMR coax is far superior to that of RG58 coax, which is among the most cheaply made, and mass produced coaxial cable out there.
for example, the RG58 coax that you used to get from Radio Shack about 20 years ago was so bad that you could see the dielectric underneath the shield braid very clearly.
i dont know whether or not its the same now because i stopped buying their coax the minute i saw that.
anyway, just wanted to put that out there, that there are other reasons for upgrading one's mobile coax run.
LC
