Take a look on the collegiate sports board : you've got an huge thread about endurance sports. I think you'll find the answer you're searching for...
IMO the best AS for endurance are :
1) Eq : increase the red blood cells count (like EPO) without too much weight gain
2) oxandrolone and winstrol : both give good strength gains, also without great weight gain, and work very well with Eq
3) masteron (if you can find it)
4) maybe deca (for joints/recovery. but a very bad choice if you're tested)
But if you can find it, (or have enough money to spend) EPO is by far the better choice, stacked with small gh doses...
For endurance , dbal and test are crap (if you take too much, and too much is maybe more than 200mg/w for test, and more than 10mg/ed for dbol) : you'll have to carry every lb when running, biking, swimming...
The only good thing is that both give you better recovery after workouts , so you can use it at very low doses. but not cycled and stacked like a BB does.
Hope this helps.
PS : nothing (no drug) can help directly for speed : only hard training/pliometrics. but if you're stronger, you can move faster