The poluurethane bushing version or the spherical rod end version?

 

Depends on how you use your car.

A rod end version has zero deflection so it's perfect for any sort of race car however it'll be hard and noisy for street use and they do wear out over time.

Poly bushings are quiet. They don't move around as much as rubber bushings but race cars don't want that extra movement. They'll last for a long time before wearing out.

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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z Pro ET Bracket Race Car
383 stroker (carbed) with double hump cast iron heads and pump gas
461 Big Block installed and ready for the 2001 racing season

Best results before the 383 blew up
Best ET on a time slip: 11.857 altitude corrected to 11.163
Best MPH on a time slip: 117.87 altitude corrected to 126.10
Altitude corrected rear wheel HP based on power to weight ratio: 476.5
Best 60 foot: 1.662

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley