Amp upgrade, speaker cables or both

Over the last 4 years I have upgraded every bit of my system except for my Analysis Plus chocolate oval speaker cables. The last major upgrade I made was replacing my ancient Kef 104/2 s with Tannoy Cheviots.  Now I am wondering if my Parasound A23+ amp is under powered for the speakers, or if I should bite the bullet and replace my speaker cable, a project I find not very interesting and potentially expensive as I have some long runs. As to the amp, I could spend $5-6000, though would be happy to spend less. I also would consider a used amp, if it wasn't so old that I had to worry about caps going bad, etc.

My system is as follows:  

Amp: Parasound A23+ 165w x 2 into 8 ohms Pre:   Parasound P6
Speakers: Tannoy Cheviots, Analysis Plus Chocolate Oval speaker cables
Digital Streamer/Source: Heavily modified BlueSound NODE 130 (added Fidelity Audio clock board, replacement PSU module & LPSU)/ Innuos Phoenix USB clock/reclocker / Gustard X26 Pro DAC (connected by Shunyata Alpha USB cables)
All other interconnects: Synergistics Research Foundation or better
Power: Power conditioner: Synergistics Research Powercell 10 SE Mk 3 w SR Atmosphere level 3 cord; All power cords SR Foundation

Listening room: WIFE's LIVINGROOM  14' left to right on the front wall, 16' deep, opening up to a dining room area to the rear. That means my speakers are in the corners of the front of the room with a large window and couch in between them, and all of my audio boxes are in a cabinet on the right wall that supports the TV. On the left wall opposite the cabinet/TV is another couch, where the end towards the front of the house partially blocks the left speaker. I have a comfy chair 9' back from the front wall, about 9' from each speaker (speakers are pulled away from the front wall)(as an aside, I got the Cheviots in part as Tannoy was a brand that my guy at Upscale Audio in Laverne said would be able to deal with my listening room, and he was right as I have a pretty good soundstage, considering).

So now to the issues:

Amp:

I am wondering if I should upgrade my Parasound A23+ amp. I wrote Tannoy, and they told me they recommended an amp with 250w x 2, and told me the max power handling of the speakers was 125w continuous, 500w peak. Needless to say, I probably never play the A23+ at more than half way up, but you always read about people talking about headroom. I was looking at the A21+ which has 300w x 2, though it doesn't seem like a much cleaner amp than the A23+.  What would you folks suggest? 

Speaker Cable:

I am wondering if upgrading that would improve SQ. The problem is that with my audio electronics on the right side of the room, I have a pretty long run to the speakers, especially the left one. I was wondering if it might be cheaper to relocate my amp to the right front corner behind the right speaker, and get a long interconnect between pre and amp. When I upgraded my amp power cord to SR Foundation in line with all of my other cords, I got one that would be long enough to go from my SR Powercell to that location.