Here are the instructions from the 1996 Ford CD. It does not say that the tensioner spring and bolt needs to be replaced. Yes, those are the correct part numbers but if they are not worned out, then don't worry about it.
Timing Belt
Removal
1. Disconnect negative battery cable.
2. Raise vehicle on hoist.
3. Remove right front wheel assembly.
4. Remove crankshaft pulley shield screws and shield.
5. Rotate drive belt tensioner clockwise and disengage drive belt from power steering pulley.
6. Using Strap Wrench D85L-6000-A to keep engine from turning, remove crankshaft pulley bolt and pulley.
7. Remove lower timing belt cover bolts.
8. Lower vehicle.
9. Remove two engine intake air resonator nuts and bolt, loosen hose clamp from inlet tube, disconnect sensor, and remove intake air resonator.
10. Remove two screws retaining coolant reservoir to fender and one screw at hose from inner fender. Position reservoir bottle aside.
11. Position floor jack under oil pan and raise it to release pressure from front insulator.
12. Note: Make a reference mark for installation reference.
Remove six nuts retaining front engine support bracket to insulator and remove bracket.
13. Remove three front insulator bolts and insulator.
14. Remove power steering reservoir line nut and two bolts retaining pump line at engine lifting eye and steering pump bracket.
15. Disconnect ignition wires from spark plugs and position them aside. Remove 8mm upper timing belt cover bolts and cover. Remove 10mm valve cover bolts. Remove valve cover and discard gasket.
16. Remove idler pulley assembly.
17. Remove water pump pulley bolts and pulley.
18. Remove camshaft timing belt center cover bolts, center cover, and lower cover.
19. Turn the engine to top dead center.
20. Using Camshaft Alignment Tool T94P-6256-CH and Camshaft Sprocket Holding Tool T74P-6256-B, align the camshafts by installing tool into slots on rear of camshafts.
21. Remove timing belt tensioner bolt, tensioner, and belt.
Installation
1. Loosely install timing belt tensioner, bolt, and belt. Adjust belt tension. Tighten bolts to 35-40 N-m (26-30 lb-ft).
2. Position lower timing belt cover. Install center cover and bolts. Tighten bolts to 6-8 N-m (53-71 lb-in).
3. Position water pump pulley, securely install the bolts.
4. Install idler pulley assembly. Tighten to 48 N-m (35 lb-ft).
5. Remove camshaft alignment tool.
6. Using a new gasket, position valve cover and install bolts. Tighten the bolts in two steps. Connect the spark plug wires.
a. Tighten all bolts to 2 N-m (18 lb-in).
b. Tighten to 6-8 N-m (53-71 lb-in).
7. Position upper timing belt cover and install bolts. Tighten bolts to 3-5 N-m (27-44 lb-in).
8. Position the front insulator and power steering hose bracket. Install three bolts to 70-95 N-m (52-70 lb-ft).
9. Position front engine support bracket and install six new nuts. Tighten the nuts to 70-95 N-m (52-70 lb-ft).
10. Lower and remove floor jack.
11. Position coolant reservoir. Securely install two reservoir screws and one coolant hose clamp screw to inner fender.
12. Install power steering reservoir line nut and two bolts retaining pump line at engine lifting eye and steering pump bracket. Tighten the retainers to 6 N-m (53 lb-in).
13. Position engine intake air resonator. Install one bolt and two nuts. Connect sensor and securely tighten hose clamp to inlet tube.
14. Raise vehicle on hoist.
15. Install lower timing belt cover bolts. Tighten bolts to 6-8 N-m (53-71 lb-in).
16. Using Strap Wrench D85L-6000-A to keep engine from turning, install crankshaft pulley and bolt. Tighten bolt to 110-120 N-m (81-89 lb-ft).
17. Position serpentine belt into place, rotate drive belt tensioner clockwise, and install belt to remaining pulleys.
18. Position crankshaft pulley shield and securely install screws.
19. Install right front wheel assembly. Tighten wheel nuts to 85 N-m (62-lb-ft).
20. Lower vehicle.
21. Connect battery negative cable.
22. Check operation of the engine.
You would need the Gates timing belt kit.
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=zetecmaint&Number=1206766&page=&view=&sb=5&o=&fpart=all&vc=1 
