At 252 Evs, 31 IVs and Timid nature, Luvdisc's speed is 322.
With Swift Swim, it will double the speed, so x2 = 644.
With Choice Scarf, x1.5 = 966.
EDIT: disregarding IVs (say speed is 0), it will be
288 (Timid + 252 EVs)
x 2 = 576
x1.5 = 864
Conclusion: Dexoys can eat its heart out.