high magnification fixed power scope recommendations

Hi all.. I finally got out of pcps and purchased a used t05 Diana air king .177.. Now I am wanting a high power fixed scope for it.. Right now it has Vortex kit in it, but came with the original spring and seal.. Now the dilemma.. In the $300-$400 range what is your opinion.. Weaver or sightron target scopes? Which has the best warranty? I also considered a Nikko Sterling C-more 30 variable since I do like them. Let me know what you think or if you have other suggestions.. Just shooting targets at fixed distances.. 
Thanks!
 
"cosmic"Hi all.. I finally got out of pcps and purchased a used t05 Diana air king .177.. Now I am wanting a high power fixed scope for it.. Right now it has Vortex kit in it, but came with the original spring and seal.. Now the dilemma.. In the $300-$400 range what is your opinion.. Weaver or sightron target scopes? Which has the best warranty? I also considered a Nikko Sterling C-more 30 variable since I do like them. Let me know what you think or if you have other suggestions.. Just shooting targets at fixed distances.. 
Thanks!
Vortek will smooth out the shot cycle, but it's still a magnum springer, and is harder on scopes than a non-recoilless one, because all the recoil goes to the scope, none to your shoulder.
I don't believe Weaver, Nikko Sterling and Sightron scopes are warranted for springers, so they're out right away. They won't last a day on a Diana 54.

SWFA is the way to go. I have their 10x42 w/ rear focus and mil quad reticle, and it is awesome. They make their fixed power scopes up to 20X. That's what I'd get, if I were you. $300.