[ParkerRS]

I have the DSE unit under my 72. I haven't finished the car yet so I can't give any driving impressions. The qaulity is top notch with beautiful welds and the hydro formed bends.
It will accept all C5 and C6 brake options as it uses C6 spindles and bearing packs. Maximum front tire is 275/45-18 on an 18x10 rim, this requires no inner fender modification for function but I will be modding them for appearance.
I can't speak for sbc or bbc applications but I can for an LS platform. The DSE motor mounts sit the engine back over 2 inches, so it is tight to the firewall requiring a small mod on the left side to clear the upper mount ear of the bellhousing.
It also moves the transmission back far enough to require the tunnel to be raised at the front to clear it. You are on your own as far as a transmission crossmember since they don't offer one. There are mounting holes for a trans crossmember in the stock locations but you give up a couple of inches ground clearance with the exhaust using this type mount. You can see what I did for the transmission mount in the project progress section under Fool's Gold.
The components are all top notch, high qaulity and fit like a glove. It has factory style bumpstops made out of urethane which are changeable. the cross shafts are stainless, the bushings are delrin, the ball joints are GM as well as the spindles. There are several shock options, all of which are AFCO's rebranded with a DSE label on the sub-frames, as opposed to the Koni's they offer with the qaudra-link. The sway bar is splined and riding in delrin bushings. All pivot points have zerk fittings for greasability. The unit slid right under the car and tucks up tight and easy. The legs which extend rearward are also not as tall as the factory unit providing almost another inch of ground clearance. Ride hieght is adjustable with the coilovers.
Customer service is excellent as well as reputation. Hope this helps.