Any aftermarket suspension with a R&P front steer has been set up to have fair to decent ackerman. Flipping to stock steering arms forward to use a rack is what produces reverse ackerman, which is a nightmare to drive.
Magnumforce is probably the first company that was mass producing coil over kits for mopars. I recall seeing advertisements for them as early as 1991. However, their earliest efforts and their base system still offered today, bolts directly to the shock towers with no direct reinforcement. This means over time and with use, the inner fender begin to collapse in and will pinch the hood. They now offer an extra price kit that provides down tube to reinforce the shock towers. They also have produced a new kit called the transformer which is a huge, bulky looking thing made from box tubing to address some of the shortcoming of their tubular system and to make a much sleeker looking bolt in solution.
Since you are still digging at aftermarket systems don't forget to look at these as well;
XV Engineering.
http://xvengineering.com/ whose coil over suspension is an aluminum square tube frame using C6 Corvette parts and a very robust 3 link rear design. User Finoke here on CC.com has one of these under his Cuda. Look for his posts on it. Well designed system but not without its own quirks and issues.
Gerst Suspension;
http://www.gerstsuspensions.com/ a recent addition to the tubular offerings that are out there. They build their stuff out of .25 wall everything, so the do not drop as much weight as many other systems, but are hoping to achieve OEM longevity. My fear with this would be that now the heavyweight system will now beat the car into submission while suspension parts remain intact.
Control Freak Suspension ;
http://www.freakride.com/ a complete rip off of Alterkation only done in square tubing. All the same issues as are found with Alterk.
If I may offer an observation and recommendation...you are obviously building a very nice car and dumping a fair amount of money into. I think your shop is pushing for you to drop a similar percentage of coin on your suspension as you have dropped on your driveline because such an awesome engine deserves an awesome suspension, and I'll grant you all the coil over systems offer a substantial amount of impressive appearance and perceived engineering. It also reflects positively on your shop when you take your car out and people ooooh and aaahh over it. This is very good PR for them and you.
On the flip side, you are installing an Elephant into a mid sized pony car. Chrysler did not gain this term of endearment on the Hemi because it is a lightweight. It is one of the largest and heaviest gasoline engine Chrysler ever put on four wheels. Functionality and durability had to be hallmarks of the original design of the systems put underneath this engine . The dealer networks had to support these beasts for a year after the sale, so durability was a hallmark. Because engineering was a Chrysler hallmark, the geometry and adjustability of the original suspension systems Chrysler used far ahead of its competition in the day and is actually still very refined by modern standards.
Nearly all coil over systems offer a few benefits over the stock system. Lighter weight, inexpensive spring prices, a multitude of spring choices, and a very sexy appearance. In the racing world, these are all primary considerations in increasing speed and reducing e.t. They also come with some drawback like increased turning radius, light duty components, and while they are built on sound engineering principles, lack the millions of miles of validation that went into the OEM systems.
By contrast, the OEM suspension is well established and decidedly old school in appearance. It offers the right mix of durability yet is not so heavy duty as to compromise road hazards with chassis integrity. The original mopar design offers nearly as much adjustability and has a track proven record on cars running into the single digit arena. Drawbacks to it are its overall weight, spring rates are not widely varied and are expensive to buy, and its adjustability requires digging extensively into mother's publications to fully understand how to adjust it all and dial it in.
You have stated this is a predominately street oriented car with the occasional trip down the 1320. I heartily recommend sticking with the stock based system in this application. This offers road going durability to stand up the real world. It offers readily available replacement parts. It has access to those key components to allow the adjustability you would want on a bracket racer. It offers the consistentcy you absolutely need in bracket racing without chasing multiple adjustments and changes. When combined with some high quality shocks and a radial friendly alignment, the OEM system can feel on par with any modern car.
That isn't to discount the coil over systems. If you are a tinkerer and want to play with adjustments they may be the ticket. If the roads where you live are well maintained, then you may not have durability concerns. They offer a range of spring choices in 50# increments which mean you can precisely dial in teh desired level of comfort and performance and by comparison to t-bars, are not expensive at all. And even I'll admit they look great and can be a great compliment to a new build.