I have a 99 Z28 Convertible with an LS1. My front sway bar broke so rather than weld it I would rather replace it. Problem is I keep finding (exc. convertible) to the right of everything or a general "this will work"/ "fits everything". But they range from Hellwig #5701 (1 5/16) to Hotchkis #2204F (1 7/16 Hollow) to Eibach #3831.310 (35 mm).

 

I'd go with a Strano Performance front 35mm Hollow front bar, and the matching 22mm rear hollow bar which will work best with the 35mm front. The front bar can be purchased separately if needed, but for the best handling I'd run it with the 22mm rear bar.

I'd also recommend a set of weld in sub-frame connectors to help stiffen up the chassis.

http://www.lmperformance.com/53014/1.html

 

I am running that Strano set-up on my convertible (I have the adjustable rear), no problems with fitment.

I have found three differences on the convertible: 1) x-brace behind the transmission, 2) reinforcing rods on k-member, 3) square tube gusset across the interior trunk pan right behind rear seats.