Neuspeed & Eibach are the best IMO
If the bar is solid, not hollow & comes with good end links/bushings the brand doesn't really matter. I have the ST bars because the rear is adjustable & they were the cheapest. My car understeers more with the ST front bar - not in use any more. I use the stock front bar with poly bushings & no front bar when off-street. Also a lower tie bar & sub-frame reinforcement should be used and/or welding brackets to frame. Larger rear sway bars can actually twist/tear the frame under heavy cornering. You may run into exhaust clearance issues, sway is more important than exhaust IMO.
24mm-7/8" is about the average size - I could easily duplicate a copy of my sway using larger steel & now that I think about it, I just might do that.
Check out the ST rear sway w/ lower tie
Functional strut bars do make a difference, just not a whole lot.