LiPo's for a CAT SX

[CW_]

Hi

Well I'm slowly getting my SX up and running now, took delivery of my battery today, but unfortunately it does not really fit. I knew height was an issue and so ended up getting the Reedy 4900 35C LiPo pack. The trouble is its just a couple of mm too long. I dont really want to start hacking at the hardcase but would rather swap it or sell it on ot buy one that fits right. So other than the speedpower packs, what are the options for a decent quality LiPo that will fit easily. I want at least 30C discharge but ideally higher and at least 4000mAh but preferably around 5000. Seen an LRP 5300 pack for a good price how do these fit? Any other good ideas?