Use a Himax 2815 3000 it is the best speed 400 replacement that you can get for the money, the best is the Aveox 27/13/3 it is about $30 more but it is about 8mph faster. I have used these setups in the slinger and the zagi and it is a marked improvement over the stock setup.

The slinger will not last long stock with a brushless setup, the best thing to do is strip off the monokote and use strapping and packing tape it does weigh more but it will withstand the G's

For you working class people that can not or choose not to spend the bucks for lipos go to www.maxamps.com and order the 8 cell pack to use with you brushless setup they are cheapest place to get batteries on planet earth, with the aveox motor and the 8 cell pack you will be able to go 90mph+ in level flight, my flying buddies and I got a wedgie to do aprox 118mph [:@]