moment of inertia...think of your car like a barbell. The closer the weight is to center, the easier it is to manage transitions. B and E bodies are larger, so even achieving 50/50 on them means their moment of inertia will always be greater than an A body. In competition, this is critical. For open track days and fun driving, much less so.
You goal of a good handling car with decent road manners is certainly achievable. Budget is a big variable. With all you engine work, it does lean towards a higher end budget, but it doesn't have to be. Do you have a target you are after here or is the sky the limit? Are you planning on competing or is this a fun day car? If competing, are there any rules constraints to the system such as NASA Time Trials or SCCA classes or is this an unlimited, run against the big guys of the sport effort?
IMO, the biggest advantage of the coil over systems is limited to a few items;
*rates from 200-2000 are easily available. This is paramount if you compete at multiple tracks that necessitate different rates. As a weekend warrior, this is much less to a non issue level of critical.
*low cost for rates changes. coil over springs are dirt cheap compared to t-bars and leafs. important for the above factor.
*potential space and weight savings. they obviously are more compact and lighter.
*potential adjustment range. This is a big MAYBE as most of the coil over systems out there have modified geometry that improves on the mopar achilles heel of caster/camber interdependance, but very very few allow a range of adjustment other than height, which a stock mopar can already do.
Shock control of suspension motion is the key to a good riding and performing suspension. Shocks are to suspension like camshafts are to engines - they determine everything about the manners and operating range. Cheaping out here can make a good system a dog and great shocks can make an average system feel superior. This allows much higher spring rates to be controlled to a degree that makes them more comfortable than their gross rates would lead you to believe.
The Hotchkis system can make a very capable fun car with all around usage and give you a baseline to build from. The price of entry here is not outragous and if you decided to move beyond that in the future, you could certainly unload the system easily.
If cost is not an option, a complete analysis and then following the suggested changes from Ron Sutton through any of his systems is probably the pinnacle of pro touring as a genre.
http://www.ronsutton-racetechnology.com/If budget isn't a big concern but you are a do it yourself guys and want to be intimate with the fabrication, Dobbertin Performance is probably the cutting edge of adapting Corvette suspension systems, including IRS, to any chassis configuration.
http://rick486.wixsite.com/dobbertinperformanceif ultimate adjustability is the goal, then an air system may be the best all around system that will handle well, cruise well, and can be adjusted from inside the car. These typically are outlawed by all sanctioning bodies for racing, but if sanctioned competition isn't on the agenda, then no loss.
https://www.ridetech.com/applications/musclecars/So, what does "track events" mean to you, how are you approaching it, what is your budget? Knowing that. we can better dial you in.
