Chassisworks has connectors with a brace that works with their as well as stock sub. I have it but not at a point of installing it yet, here is sample:
http://www.superchevy.com/how-to/cha...nector-system/
Other nice option is a complete spec frame from roadster shop, would need to look into fitting shockwaves instead of coil overs. Saw it a the Syracuse nationals, a really nice piece and I think price (under 10k) is really attractive when you think of loading stuck sub with nice parts, or buying complete sub, frame connectors, brace, rear 4 link or torque arm and then a tiger cage for instance or custom cage. Here is a link and there are few videos in there as well few floating around the net with that frame on a track, check it out.
http://roadstershop.com/product/full...-spec-chassis/
I'm personally went with stock modified stock sub also with all ridetech set up and shockwaves, dse mini tub, modified chassisworks g link/fab 9" all to get a low stance that I personally desire, also with ridetech shockwaves on the back of the modified glink. Lot of work went into modifying front sub, rear floor and the g link to achieve my desired ride height and truly slammed look when fully aired out. Don't think I would even achieve same desired stance with a spec frame, but everyone's taste is different and everyone has different capabilities.
But if i were to do it again, I d really consider trying out the rs spec frame, that it also comes with rear 9" housing and 31 spline axles included,no floater end tho, but pretty sure that could be an option...
Won't get a first gen much stiffer and squared up then a full frame. There will always be some pros and cons with whatever set up you go