These type of threads are hard to answer because a book could easily be written answeing this question and other points raised.
You will actually get some of this answered as we're doing an article with one of the biggest mainstream automtive mags out there next month where they will be doing a full evaluation of a full tilt car (XV001) and we're providing a stock 70 T/A as well. The differences from our own testing were extreme to say the least, so I'm not sure how detailed they will go in terms of comparison, but they will have a benchmark to see just how far it can be taken.
The stock setup definitely does not handle well by todays standards.
It can be made to work much better for sure, as we have done with our Level I suspension.
With that setup we've pulled 1.0 sustained (not peak) lateral G and significantly improved the handling and ride in virtually every other way.
So the stock type setup can be made to work. However, I don't know that I'd say you're going to go and eat up everything new that's out there running T-Bars and leaf springs. Significanly better than stock without a doubt and definitely useable on a track where you can have a great time and get very respectable results, but not what I'd consider world class.
Level II was developed to take the cars to that level. Most of the components are aluminum (including the K), all the geometry is optimized based upon current suspension technology, components are all matched and dialed in, all designed to be stong and light and also reduce unsprung weight - and we use modern race quality high pressure monotube shocks custom valved for each platform we support. This was designed to run with the best modern cars.
It's also important to note that we did not do this as a full race setup. However, it is a full road race quality suspension basically de-tuned for the street so it can be pounced on track and still provide good ride comfort on the street - which is what my expectation of a really good modern performance car is. It could easily be dialed up for a full race application, but as someone else pointed out, no one's really campaigning these cars anymore (someone really does need to run a car in the American Iron series though).
We will shortly be announcing an open track event that we are putting on at a real road race course and will be open to whoever wants to attend - up to the number of cars that can be handled. It will have professional instructors, class time in the AM and plenty of time for people to see how their cars actually work on a real road race course. The event will be for American musclecars only - but not limited to just Mopars.
Want to see how our cars run in person - here's the opportunity and we'll probably give some rides as well.
The DVD referred to is is all the thirteen episodes we were on Dream Car Garage last year and is up on our website and can be bought for $4.99. Visit us here or at shows and we're happy to just give you a copy. Come to our open house we'll be giving those out to all that attend as well as some other goodies. Anyway, that DVD shows stock, Level I and Level II on track. The last segment shows XV001 running full tilt on a large fast road race course. Watch that first and then judge for yourself. Rest of the DVD shows how we developed and tested - if you're a hardcore gear head you will really dig it - people have told us it is "Car Porn" - we thought that was awesome and laughed our butts off. Much of what was used is straight from the OE level and the highest levels of professional motorsports (i.e. F1, IRL, Grand Am, ALMS, NASCAR, CHAMP) - we used the same engineers and tools. We even used a ride and handling specialist that gets loaned out to the OE's when they have issues w/ their production vehicles.
All of that was also used on the Level I setup, so it is pretty much as dialed in as can be for a stock type suspension. All the components are matched, which unless you have tons of time on the track to try every T-bar, shock setting, shock type, sway bar size and have leaf springs made up in different rates you won't get to - that is the value in our Level I - it's ll dialed in, matched and optimized. For example, we found out immediately that to make the cars handle, the T-Bars were way too light and the leaf springs way to heavy - so we have much larger bars made up to our spec and very light rate leaf springs which our shocks are dialed in to work with. Anyway, this is how race teams do it - you test, dial in, eliminate weaknesses and optimize. No one else offers that.
If you haven't seen any of these before, here's some shots taken the same day the last segment on the DVD was filmed on track.