I agree with SpeedX.
Slowing down Outlines will slow down whole print significantly !
In Slic3r this is one of the most important settings for me.
For High Quality prints in Slic3r I use:
200mm/s for infill
140 mm/s for Perimeters
80mm/s for Outlines
60mm/sec for small circles.
With this settings, Slic3r makes a print 30-40% faster than with S3D by same quality.
Frank