[David A. McDow]

The gap you are seeing is because the rubber strut bushing is worn out. It might be the springs are tired too. See Figure 10, green arrow Volkswagen Jetta Mk4 Front Strut Replacement | Jetta Mk4 2.0L (1998-2005) | Pelican Parts DIY Maintenance Article
If you are looking to lower the car (I've never done it), I belive you are looking for "coilover" springs.

 

[David A. McDow]

Thanks for the insight. I’m wanting to go the opposite way and add a lift to the car. The terrain on the Big Island (Hawaii) is hard enough on cars so adding a couple inches is definitely the way to go.

I put these on my '01 and '02 Jettas and love them. They will lift the car about 2 inches in the rear and 1 1/2 inches in the front: Lift Spring Set (Mk4 Golf & Jetta Sedan)
Strut Spacer Individual (A4)
It's easily a DIY if you have the space and tools. Plenty of how-to's on the internet.

Edit: Metalnerd makes a lift, but I've never installed one Lift Kits for VW® MK4 Chassis Golf®, Jetta® and New Beetle®