Please read through my post below as I go into depth on tow capacities and determining spec on each component of towing.
I have an 07 XLT, 280K miles, tow a 23' travel trailer at just under 6,000lbs for summer trips. Everyone has there opinions but its up to you to learn your own abilities and capacities on towing, especially full time.
My towing post
Tow Guide
Based on the vehicle and trailer you given:
2015 EL: EL specs
Towing maximum: 9,100lb
Payload Capacity (You and your stuff in car only): 1530 lbs.
GCVWR: 14,900-15,300lb (depending on gearing)
3325BH: Trailer
Shipping (DRY) Weight: 7,827 lb.
Carrying Capacity (your stuff in trailer): 1,673 lb.
Hitch: 950 lb. (don't know if this is fully loaded value)
Fresh Water: 43 gal (334lb)
Lets add some numbers:
w/o fully loaded trailer: (7827lb ÷ 9100lb) x 100 = 86%
w fully loaded trailer: ((7827lb + 500lb stuff + 334lb [water if carried full]) ÷ 9,100lb) x 100 = 95%
GCVWR 15,000lb - 6500lb (loaded and full tank) - 8,500lb (fully loaded trailer w/ water) = 0lb remaining
Technically based on ROUGH numbers, you could tow this and a trailer dealer will not go through these numbers for you nor with you, they just want to make the sale! The trailer is a bit long and heavy in my opinion. You will be risking a lot with this particular set up. If you get in an accident with this setup it will automatically be your fault. If a highway patrol weighs you and your over any sticker limits, you're screwed. Towing big things is no joke and you must take it seriously. You don't want to put your family or other motorists in danger.
I hope this helps. Good thing your asking questions. We all have experience here and some are willing to share and others are just critics. But YOU must do YOU'RE own research. Watch a lot of You Tube videos on setups. Don't forget the ones that crash so you know what not to do.