Recommendations for cables based on components

I'm looking for some advice.
I'm currently using a Luxman 505UxII  amp with Harbeth SHL5 XD speakers and recently acquired a pair of Dynaudio Heritage Specials. I'm using a set of cables from Amaz.. GearIT 14AWG Premium Heavy Duty Braided Speaker Wire Cable (25 Feet) Dual Gold Plated Banana Plug Tips - In-Wall CL2 - Oxygen-Free Copper (OFC) Black $23.
Any recommendations out there for upgrading these cables keeping costs in line with current equipment?   I really  am at a loss on budgeting for these and am thinking < $500. Would cables costing $300-500 for example have any improvement over my $23 ones? I do need 20-25 feet though due to room set up. Thanks  so much.

" Would cables costing $300-500 for example have any improvement over my $23 ones?"

Depends. Best to try cables that you can return if you don’t like them.

Given the length of cables you need (I suspect you are talking 25 foot speaker cables) I would suggest you rather buy a good power cord for that Luxman and leave all else as is for now.

A pair of worthwhile 25 foot speaker cables that will make a noticeable difference will probably exceed your budget. Somebody else may have a recommendation that falls within your budget, but I don’t.
It is very likely you can get better sound from upgraded cables. What is your sound source? Digital / analog? How does your system sound now… I mean does it sound perfect? Thinking a dit more detail or just more of what you have? Do you really know the sound of your system? Make sure you really know it. Many hours of listening to the components you are buying for.

Your tastes are critical in this. So typically is just best to try some. From a dealer or rent on line. Used is a great way to double your buying power. I am guessing your system is in the ~$10K range. My rule of thumb would be invest at the 10% - %15% of system. But that is completely dependent on what you hear. Don’t go cheap on the first try. If you try some really good cables and they don’t make a difference you want to hear it. If the difference is big… then you may decide it is worth it. But that is ultimately the point… the sound improvement must be worth it to you.

I guess I would start with the speaker cable. There are pros and cons to doing all or one at a time. There can be a real advantage to all of the same brand. 

This can be great fun… or it can be frustrating. I spent hundreds of hours comparing, developing a set of parameters to listen to and scope. My listening skill vastly improved over the decades, make it fun.

Good speaker cables are really important and expensive. Can you rearrange your system to reduce the run. I usually have speaker cables for decades.  Well worth a sizable investment.
Any recommendations out there for upgrading these cables keeping costs in line with current equipment? I really am at a loss on budgeting for these and am thinking < $500. Would cables costing $300-500 for example have any improvement over my $23 ones? I do need 20-25 feet though due to room set up.

Several factors to consider here. First yes for sure there are huge improvements to be made with better cable. And yes I do mean huge. Like you won’t believe. The question of how much to budget is in one sense no different than any other component. Wire is every bit as much a component as amp, speaker, etc. So like ghdprentice said, well worth sizeable investment.

f you were talking about building a system and the subject was speakers you would certainly consider allocating a lot more than a couple hundred bucks to speakers. Same for cables. Do not make the mistake of under-allocating because it is "just wire".
If yours was a normal system, speaker cable 6 to 10 ft, I would say invest time and money in finding something really good. Because that length can easily be sold later. And that short you can afford some real high quality. At 25 ft though resale is marginal at best, making quality way too expensive both on the front and back end.

What you should do in your situation, read up on this helix cable This is something you can make yourself, get way better quality than anything you can buy at that length, and then later on when your system changes it can be easily cut down and/or reconfigured to even higher quality without having to spend extra. I am not usually big on DIY when it comes to cables but there’s exceptions to everything and this strikes me as a prime example.

There's guys on here with tons of experience building these things more than happy to help. What we're here for.  
If I were in your shoes I wouldn’t think twice about ordering a pair of 25’ foot Canare "star quad" 4S11 speaker cables with your choice of connectors from Blue Jean Cables for a total of $164 plus shipping.

They are entirely adequate.

And although it is getting old to bring up, there is a good chance the music you are listening to was originally recorded at the studio using this wire.
Why 25 feet OP what’s the deal? 3 meters is a push 2 is better. Is there any way you can move things? It’s just too long for a better solution all around. Higher quality cables, and shorter for a much better SQ, dollar for dollar..

I dare say if you just shorten the cables you already have and get them off the floor, you would start noticing a change.. Just sayin'

I recently upgraded from cables in the $50-$70 range to cables in the $600-$800 range for my system. It made a big difference in my system. Before I committed to purchasing the cables I used the Cable Company’s lending library option. It allowed me to try a couple brands in that range before ordering them. DH Labs Silver Sonic speaker cable is available in custom lengths. A pair of 25’ speaker cables is $550 on that website. I tried that cable and it was an improvement over the what I had been using. 

I suggest trying a few brands from their lending library. It will at least let you hear if there is a difference to you.
Hey, thanks so much for your response. Good idea
How does the Harbeth SHL5 XD compare to the Dynaudio Heritage Specials? Both good speakers I believe.