I was getting consistent 5.7 0-60 times with just traction and stability control turned off and very consistent 5.8's with Cobb's traction control and stability control turned off, which I was happy with since torquey FWD cars aren't the greatest from a dig. However, after installing my RMM and using Stratified's traction control with stability control off I've been hitting 5.5-5.6 seconds. This is according to the 0-60 setting on my accessport.
The TB Performance Torque Gusset paired with a stiffer RMM (in my case the mountune one) reduces torque steer and wheel hope to almost zero on stock power. I would say you gain a couple of tenths with just these two things. Much cheaper than an LSD, so I would start here then tires then LSD. What kind of power are you making? Stock power wont get you below 5.8s-5.9s (from 6.2s stock) even with a RMM, Torque Gusset, better tires, and LSD.
These three basically just named all of our options. The TB Performance Gusset bar is a beast which instantly helps reduce flex to prevent torque steer and wheel hop (torque steer requires subtle adjustments which slow you down since any direction except perfectly straight is slowing you down...and if the cars ESC tries to kick in it's literally braking to help you straighten out) and wheel hop obviously slows you down since your tires are skipping instead of putting down power.
LSD is a rather obvious yet expensive one that helps you put down the power even better as opposed to our stock "Electronic Diff" that utilizes braking and junk that slows you down and blows in the snow/bad weather.
Rear Motor Mount is a HUGE improvement that is a testimate to why it's arguably the most recommended mod on this forum along with intercoolers and stuff. Wheel hop killer for sure. Don't worry...the annoying vibrations go away after 100-200 miles when it breaks in
As also mentioned..Cobb/Stratified Traction Control which uses spark retardation to minimize spin instead of the stupid stock system which uses brakes (throws off weight distribution and obviously using brakes while accelerating hurts) just remember to turn off the stock system or the Cobb/Stratified system won't work...oh and play with the settings. A decked out car can use less slip and have better results.
Big one here...there are only 4 spots of the entire car that touch the road, two of which are the only spots that power is transferred to the road...cheaping out there is an obvious performance killer. Get good tires. It's expensive...and I need them too and I'm dreading that bill...but the difference is so worth it.
Additional stuff not usually mentioned:
Suspension bits. Coilovers go a long way with helping the car's weight distribution and weight transfer off the front tires that are providing power. Also, lower center of gravity helps more than you'd realize.
Power. Duh, right? Add power and it'll improve, but that's not really what you're asking and you knew that already.
Weight reduction. Lowering your weight by 100lbs is enough to see noticeable results on a drag strip...meaning it improves 0-60 too. Science and sh**.
Final one? Sure, you. You need to practice, practice, practice and get better at launching this car...it's already hard to launch...and each mod listed above changes it pretty noticeably. As you learn how to launch better and more smooth your times will improve. Do it on a prepped surface like at a drag strip and it'll only get better.
It's not a straight line car, and 0-60 isn't what it was made to do, but if you work on it and get all the necessary components you can improve it.