While certainly recabling brings out the best in the k1000s better amplification should be the priority. You will get more going from the grace to a sig30, first watt, woo 5, Eddie Current HD2
... then the SAA cable and the Grace will provide.
If you have the money then yes you should get the SAA cable it is the icing on the cake but the amp is the cake.
I tried the first watt with the minimax preamp and it was an awsome combo but used you are at around 2k for that rig, the sig 30 is not as detailed but is "musically relaxed in a way that effortlessly lets the music through and used you can get them for 1.5K the Woo 5 comes in at 3k (closer to 3.6 to 4k when you factor in upgraded tubes and IMHO this amp seriously benefits from it) and the HD2 pricing you'd have to email Craig for that and to check that he does overseas sales.
Each rig has it's up and down sides I've owned the sig 30 and first watt and find the HD2 to be better than both also it does balanced cans and single ended as well as speakers . The Woo will do the same with the exception of balanced.