The 4.9 puts out about 200 horse and 275 Torque. There really aren't any aftermarket parts available for that motor, but most people who use it will tell you that it doesn't need aftermarket parts. The "fun factor" is there right out of the box. But you will need your computer modded, which will give you around 10-15 horse and the same for torque.
Bottom line, Cheap V-8 power and sound, can't hardly be beat by anything on the street in the "stop light drags" I personally would have a 4.9 in my 88, but I found a turbo car and bought that instead, which is a ton of fun. 
Eric
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Used is such a harsh term. . . I perfer "Previously obsessed over" ;)
88 4 cyl 5 speed: All show and no go
86 SE V-6 Turbo 4 speed: All go and no show
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