[purplept]

zzrogue - welcome to the forum. The strut tower brace makes less of an improvement than the anti-sway bars. It stiffens up the front suspension by connecting the two front suspension struts (those two black round metal pieces with three bolts on each located on top of each fender well towards the rear that the front McPherson struts are attached to) together with a stiffening bar so that the front of the car has less flexing while cornering making it feel flatter and more solid. It also costs less than a complete anti-sway bar set and is easier to install.

The Eibach front anti-sway bar is smaller in diameter than the one that came on your car from the factory. The reason for that is so that the front end of the car "bites" more while cornering. This is a good thing because front wheel drive cars like the PT Cruiser have a tendency to plow or understeer while cornering, the car wants to go straight but you want it to turn. If you keep your stock front anti-sway bar, I don't think the strut tower brace is necessary. In fact, it might even make your car handle worse. However, the Eibach rear anti-sway bar reduces lean while cornering which dramatically improves cornering performance. Both bars also have harder bushing material which also makes for a more solid feel. Your car didn't come with a rear anti-sway bar although Chrysler says that it's built into the rear axle assembly.

As important as those upgrades are, it is probably just as or even more important to upgrade your front struts and rear shocks. Your lowering springs put greater stress onto the struts and shocks making them work harder and beyond what the engineers intended. You probably have already noticed that the rear end likes to bounce more than it did before you installed the lowering springs. This can be dangerous because you have less control in emergency situations plus the struts and shocks wear out faster.

Another dramatic handling improvement you might consider is replacing the stock tires with much stickier performance tires, especially "summer" tires with a shorter profile like a 45 or even a 40 series. Your car came with a 50 series which flexes more while cornering which reduces control. However, the shorter profile tires will make the ride harsher because there is less sidewall height to absorb bumps.

I hope this helps.

P.S. You should probably post questions like this in the "Turbo" portion on this forum since your car is the Turbo version.