I'm also working on a LST conversion. I already have a MMM 2200kv combo, but need to install it and also need to buy batteries.
I heard+saw that the LST (7 kilo) has a HUGE acceleration with a 2200kv combo on 6 cell A123. So I wouldn't buy a 1527, but a 1521, because with the 2200kv motor (Looks like the 1515) it already has tons of acceleration. You will rip it appart with a 1527, I think.
Now, about the batteries; I'm also planning running those TP 40C packs 2x3S in series. Somebody on this forum used them and said they are great! But I deffiniteley wouldn't buy cheap batteries! I also think a minimum of 30C and 5000mAh is a must have!
Look this video:
http://www.youtube.com/watch?v=meGhxPOjVmM
In that video he uses a cheap chineese motor, 10XL with 1600kv or something. And he said to me that the 2200kv castle-neu motor had a LOT more power + speed! So a 1527 would be totally redicolouse!