Running / Endurance Without Sacrificing Strength

Hello everyone. I do contractual work for a living that requires I have a (relatively) high level of fitness, namely timed 5k and 10k runs on top of measuring the 'big lift' total (bench + dead + squat). My issue is being able to run ~19 minute 5ks without completely destroying my strength. Over the last few weeks I've tried to shift yet again from strength back to endurance but as my weekly mileage goes up my strength takes a dramatic dive.

I'm 25.

1 Month Ago:
Bench 275, Squat 405, Deadlift 365 (1045 total)
195# bodyweight, ~16% bodyfat
~24 minute 5k
~55 minute 10k
< 5 miles a week running, low impact cardio 3x a week 40 minutes

Currently:
Bench 245, Squat 375, Deadlift 345 (965 total)
180# bodyweight, ~12% bodyfat
~22 minute 5k
~50 minute 10k
15 miles a week running, 2x time trial 1x LSD 1x interval 1x tempo


My buddies are recommending either a test-e cycle or winny to help me meet all of my goals (1k combined lifts, 19 minute 5k, 47 minute 10k). I have 2 cycles of prohormones under my belt but no straight test. For the record I cycled on/off properly and did my due diligence so no worries on me being a negligent user. It's worth mentioning that drug testing is a non issue. I've read contradictory information in regards to increasing RBC, test-e having too much water retention to help with running, winny being bad for distance running (I never run over 15k), etc. I'm just looking for someone to help clarify things.

So: what should I do to help increase my running ability without completely sacrificing strength? Test-e? Winny? Neither?

Thanks for the help.

There seems to be in inverse relationship with strength and efficiency. My first step for any endurance athlete is to do a VO2 test. That will paint a better picture were your maximal speeds and Lactate thresholds are. This is relatively cheep compared to getting buying a cycle of test-e. From there you can hone in what specific targets you want to train. I would say EPO would be a good choice if your are serious. Augustine has put out an awesome post for those doing their first cycle. Check it out. This includes really fine tuning what you do. I don't think anobolics is a magic bullet for endurance athlete. But it does help. The purposeful you are the better it can work for you.