No, there's definitely a different sound for slow-jumping ships. If its the same sound played at lower speed, the difference is night and day. I tried it out on a Starfairy and thought it a vast improvement. Your own mileage may vary, of course, and if you're eventually going to be replacing the sounds anyway it doesn't really matter.
One other thing I was curious about - I've noticed the lack of sounds in the space battles, and I think its a great, realistic touch. However, were you planning to have sounds for weapon impacts, when bullets and the like actually strike your ship? You'd hear that part, after all.