I'd reckon the Jeep would be fine for towing your Z. Just get a good trans-cooler kit, a temperature gauge and it will do what you want it to perfectly. Also make sure that the brakes are in tip-top condition every time you leave to go on a trip.
Assuming your Z and your racing equipment weighs about 3400 lbs, you're still 1600 lbs below the tow rating, which is plenty of cushion. Those 4L Jeep motors are damn near bullet-proof, so I would not be too concerned about reliability. Just keep up with the maintenance, and I'd be willing to bet a 750 dollar Jeep goes a long way.
Good luck!