I wielded on a tab with a hole in it on the down pipe close to the cross over connection. Then used a spring to pull the down pipe to a small hole in the cross over tube connection flange. I'll take a pic later when theres light out to show you how it is on mine.
The schematic for the 088 ATS kit shows a long narrow angle bracket that ties the down pipe to the engine somehow. What might be easiest if you don't have a wielder is to use a pipe clamp to attach a hook or really tough spring from the downpile to the engine. Although I've noticed that my DP will stay in place even without anything to tie it to the engine.