I did full poly, HD bils, lowering springs, IPD sways, Adjustable torque and panhard rod over 70,000 miles ago on my '88 240. It rides like the day I put all of it on. I'd do it again in a heartbeat.

Know that you will have a little more road noise and feel. I'm guessing I'll get 150,000 - 200,000 miles out of this set-up. Anybody?

The only bushings that might need replaced are the front suspensions rear control arm, rear suspensions torque rod and trailing arm bushings. Other bushings rarely go bad or do so at much higher mileage.

I would and do use poly on the control arm and torque rods and use Boge rubber on the trailing arm. This use of poly does not affect ride or noise quality. I have done this on five 240's the oldest has been in service for 4 years with no problems.
Dan

I've got 117k mi. on my highest mileage car with SuperPro poly bushings at this time. I've got no complaints with them at all. They do ride somewhat stiffer than stock rubber, and therefore transmit more road noise and are a bit more harsh overall, but I like the feel of the car much more. I reach for the poly bushing catalogs for all of my suspension and accessory bushing applications on my 5 Volvos.