Sparks are usually normal, can be a bit of a shock (pun!) the first few times, it happens, but it just becomes part of a routine, then you get worried when it doesn't spark!

My 8XL ran very hot with a 4S a123 setup, but I have a very heavy truck, and tall (i think thats the word, 20/51) gearing. Have since upgraded to a NEU 1515/1y and it runs cool with the same setup. Worth the money, just start saving your pennies hopefully you will have enough when your 8xl dies.