OffRoaderX

For most normal people, GMRS is not a hobby.

That question has been asked a few times.  You would need to bypass the built in duplexer and replace it with a duplexer capable of withstanding the greater output power.  Technically it might be done, but practically it probably isn't worth it.  

Thank you.

For most normal people, GMRS is not a hobby.

Thank you.

I've been using LMR400 on my repeater for over a year-and-a-half and it has been plenty "good enough" for me and everyone in the several hundred square miles that the repeater covers.
Is it as good as a multi-thousand dollar commercial-grade repeater installation?  NO
Will the coax last forever? NO
Does it work? YES
Be wary of "some people" that love spending other people's money.

He has (or will have) a repeater with an SO-239 connector.  He already has an antenna that has an SO-239 connector. He has LM-400 feedline that has PL-259 connectors that will mate directly to the antenna and repeater, no adapters needed.  In terms of loss through connectors, that’s the least he can make it, regardless of whether he uses hardline or anything else.  If he gets a jumper with N connectors on both ends he would have to add N to PL-259 adapters, which (using your numbers) would add 1 dB loss and negate the 0.75 dB difference (your numbers for the loss through 25’ of LM-400) in losses through the feedline. 
But what are the losses through 1/2 “Commscope?  The losses per 100 ft (according to the Commscope website) are 2.342 dB or about 0.55 dB for 25 feet.  So, by using Commscope Superflex and two adapters, the losses are 0.56 + 0.50 +0.50 or 1.56 dB So now he’s 0.8 dB negative compared to using what he already has.  
Yes, he might decide that he doesn’t have the coverage he wants and decide to buy an antenna with more gain.  He still has that as an option. 
“But I digress I keep forgetting the hobby is about doing it as cheap as possible as hams do in this new age.” 
Way to lash out at both hams and those who have already stated they don’t have deep pockets.  

You (and everyone) is welcome to join our National Net via Zello, every Thursday night at 7PM (Pacific).. No Facebook, no dues, no fees, no mandatory meetings.  See how here:  https://www.notarubicon.com/zello-gmrs-repeater/

yah... About that......

It sounds like your computer is incorrectly trying to open the compressed (.zip or .rar) file with Adobe.  Try to manually open the file with your Unzipping program, or look up how to change the association between whatever file type it is and Adobe.
Also - for clarification - you dont need "the driver", you need the programming software.

I've been using LMR400 on my repeater for over a year-and-a-half and it has been plenty "good enough" for me and everyone in the several hundred square miles that the repeater covers.
Is it as good as a multi-thousand dollar commercial-grade repeater installation?  NO
Will the coax last forever? NO
Does it work? YES
Be wary of "some people" that love spending other people's money.

I've been using LMR400 on my repeater for over a year-and-a-half and it has been plenty "good enough" for me and everyone in the several hundred square miles that the repeater covers.
Is it as good as a multi-thousand dollar commercial-grade repeater installation?  NO
Will the coax last forever? NO
Does it work? YES
Be wary of "some people" that love spending other people's money.

TNRonin,
Youre getting good advice from radio professionals about the best antennas and feed line. That’s great if you really want the best. If that’s the case simply ignore the rest of this post. 
If you’re still reading you might be a hobbyist who’s just interested in “good enough“ and the financial savings that implies. 
You already have LM400 feedline. 
I think you already have a J-pole. 
A short run of LM400 will have nearly no discernible incremental losses compared to hardline. Just make sure you seal the connectors against moisture. 
A better antenna will make a difference, but how much is that worth to you?  
Hook up what you have and try it. It won’t cost you anything but your time and I guarantee you’ll learn from the experience. Then, if it doesn’t work like you want, you can always try a different antenna (or perhaps raising the j-pole). You can always upgrade the feed line as well. 
I would hate to see your enjoyment of the hobby diminished because you’ve been convinced that what you have isn’t good enough when the actual incremental improvement is only measurable to professionals. 
Don’t let the best stand in the way of the good enough. Lots of people use LM400 and j-poles with inexpensive repeaters and do just fine. In the end elevation and location are the most important factors and all the money you have cannot overcome that. 
 

According to the FCC Enforcement Database, since 2012, there are no ramifications.
Unintended consequences include more "pure" spectrum-use since virtually every LMR radio is better designed and has far less spurious output than pretty-much any consumer GMRS radio on the market.

It doesnt matter, and only the hall-monitors care - as you can see very clearly in this and other online forums..

Everyone in our GMRS group uses MDC so we know who is talking and/or what radio they are on.

This is ideology is a result of the constant barrage of ham radio operators acting like snobs, idiots, and whatever (take your pick) in online forums every day seemingly doing their best to chase away newcomers to the hobby.  And yes, GMRS users also do this, but strangely, many of them also have ham callsigns listed on their forum signatures.

He is correct though, it would be easier to help if we knew what radio the guy was using.. And I prefer his direct and to-the-point replies to the 5-10 paragraph uncecessarily-complicated answers that always include a full resume of the person leaving the reply as well as a list of all the radios they own.
I guess we all have different want/needs in forum replies..

My radio, my choice.

I have looked myself (at the last 10 years of enforcement), thats why I dont trust what you're saying.

Not that I dont trust you, or think you're making stuff up out of thin air, but i would love for you to share some actual facts about all these others this has happened to.  Perhaps a link to the FCC enforcement database entry?  Because as I'm sure you know, every time the FCC breathes down anyones neck, for any reason, by law, the FCC must publish that enforcement.

I keep my Roger Beep on - when someone complains about it, I remind them that its my radio and nobody is forcing them to listen to me.

If you look close, 99% of them are actually sad-hams, disguised as GMRS operators.