I have done a mock up of SRT8 manifolds in an early A using coilovers. The only issues are very little (1/8 inch) clearance on the pass side and the bell housing needs to be trimmed by the starter to give the manifold room on the drivers side. The coil over conversion can be done using a Dillenger support kit for the shocks, and coil overs. This allows the notching of the subframe where the T bars were for exhaust pipes to run, which is a great mod allowing the pipes to be tucked up under the car for better looks.
I plan on using the fuel cell I already have in the trunk, cut out the spare wheelwell and replace with a flat piece of steel and put the mufflers under there for a decent look.