Help with first cable upgrade.


I have a Musical Fidelity v-150, rotel rp-3000 turntable and an old Sony CD player.  I have 2 sets of speakers B&W CM2's and JM Lab chorus floorstanding speakers I may have to part with due to space.  My power cables and interconnect cables are cheap stock.  My speaker cables are a 20 year old or so set of MIT shotgun cables.  Any recommendations for budget friendly cables that may help the bass or soften the brightness of my system?  Thanks.
shimanole
It is a nice system, but not at the level of resolution required to perceive any difference whatsoever attributable to cables.  These guys are leading you down a primrose path that will only lead to disappointment.  You would be far, FAR better off with a little Schiit Loki equalizer to tailor the sound.  
QED silver anniversary xt speaker cables are excellent and should help. I use the bi-wire version.
Get them here...https://www.futureshop.co.uk/brands-category/qed-cables
Replacing the cables that are still the nasty OEM ones will give you the biggest benefit. 

I would suggest you buy a single powercord, that you should put on your Musical Fidelity v-150. The audience house sound is probably what your looking for - they have a special on their Forte F3 cables which is a very good entry level cable and a significant upgrade over stock. Another cable I would recommend that is not all that expensive (< $150) is a Wireworld Aurora. Both well should give you a very audible improvement.

Buy what you're comfortable affording and preferable buy one (1) better quality cord than two or three lesser/cheaper models. 
Jnorris.  Thanks very much for your post.  I think I will seek an equalizer of sorts as I agree my system is somewhat low end and maybe my expectations should be tempered like the treble.  If I find a cheap upgrade for a power cord, speaker cable and interconnects I may pull the trigger with fingers crossed.
I spoke to tech folks at The Cable Co., Audioquest and Silnote and I must say, there is a lot of disagreement regarding sound as it relates to oxidation, stranded wire, solid wire, coated wire etc.  I think deep pockets make these experiments much more enjoyable whereas for me, it's an investment in music that requires a return, otherwise, I'm just throwing money away that I could use for food lol.

Thanks to everyone for taking the time to post recommendations.  I will certainly look at those cables if I pick up some replacements.

Cheers!
@shimanole

I don't know how "old" your "old" Sony CDP is, but the one I had way- back-when was terribly bright.

Can you borrow a different CDP and see what effect that might have?