If cost was no object is only part of the question.  How will the car be used?  Recommendations for a cruiser are going to be different than for a thinly veiled track car.  

The other thing is that the front suspension is part of the equation.  A chassis, like an engine, is all about balance.  The parts must work together, or they end up working against each other.  These cars are what my neighbor would call "a flexible flyer".  The unibody in them is a rubber band.  If you don't address unibody stiffness the best suspension in the world is going to be meaningless.  Subframe connectors are an absolute must.  Some form of roll bar is also a good idea.  A shock tower brace is a good idea if you go the route of keeping the shock towers.

Personally I think you can do A LOT within the existing design with springs, shocks, chassis stiffening, the Shelby/Arning drop, etc.  I'm not a huge fan of rack and pinion steering in these cars.  I think a steering box setup gives better road feel, and a lot of R&P systems compromise turning circle.  I'd go electric power steering (EPAS) if I had it to do over again.  You could go to a coil over Total Control front system for like $3,500 if you really want to spent a bunch of money.

A Mustang 2 system is a great option, BUT you are going to change the car in a way not easily changed back.  

The thing is, you need to figure a budget for the entire car too.  Having a great suspension and engine and no money left to buy decent brakes is a terrible place to end up.  

I went with the R&C MII coil over setup. Not because money was no object.  It was my cheapest option for my build.  Now if money was no object, then I'm not sure what I would go with. It would depend on my plan of use for the build.