The stock SHO suspension uses bushings made from rubber. These no-maintenance bushings are satisfactory for most drivers, but for competition they may allow too much change in suspension geometry for the driver's tastes.

Stiffer bushings will increase ride harshness; whether it's tolerable is left to individual taste.

Benefits

Strut Rod Bushings

The urethane strut rod bushings are definitely a plus, there is little noticable ride degradation, their main advantage is limiting the suspension's unwanted toe changes during cornering. Initial turn-in feel will will improve and the rear will be less likely to step out because its not toeing-out during cornering.

Sway Bar Bushings

A little ride degradation, and you'll notice a bit more road noise transmitted into the body, especially in the rear, as these bushings are on the body. The front bushings, are somewhat isolated from the body by the subframe so there's less transmitted noise. You will notice a bit quicker transition of the swaybars with harder bushings, with somewhat less body roll. This is because the bar is not able to deform the harder bushings (see Delrin caveat below), so it works more effectively in torsion, transferring suspension loads as it should.

Materials

Alternative bushings are available in polyurethane and sometimes Delrin. Each material has its own unique properties.

Delrin

Delrin is a Teflon-impregnated material that is much harder than rubber or polyurethane. Because of the Teflon, Delrin is self-lubricating and thus does not require greasing in order to eliminate squeaks. It should be lubricated in order to mitigate other problems, though. Read on:

Some owners have experienced premature wear of these bushings in swaybar applications. The swaybar is just starting its transition from straight to bent in the outer third of the bushings, so as the bar rotates, the bent portion is spreading (and subsequently wearing) the bushing. The stock rubber bushings don't have a problem with this as they're soft enough to conform (or deform, if you like) as the bend rotates. The Delrin bushings tend to get hogged out and loose on the outsides of the bores.

Other than the noise from the bar rattling in loose bushings, the wear shouldn't be that much of a problem unless it gets bad enough that the bar can wander excessively from side-to-side. It might travel far enough to hit a tire when the wheel was turned sharply. One could get some split collars and put them on the bar at the insides of the bushings to keep the sideways movement to a minimum.

Frequent lubrication seems to be the key to long life. I put grease fittings and grease grooves in my bushings so I can re-lube them regularly. In lieu of that, an occasional spray with a light, teflon or silicon-based lubricant should help. Use one of those spray cans with the small extension tube that can get into the saw cuts that separate the bushing halves.

Polyurethane

Polyurethane is a widely used material for aftermarket bushings. In some applications, polyurethane bushings are prone to squeak. This is because the poly bushings are hard enough that instead of flexing within the material (as stock rubber bushings do), they move relative to the suspension piece that they are holding in place, resulting in a squeak. They need to be lubricated (white lithium grease does the trick) in order to prevent squeaking. In some locations, a grease fitting aligned with a hole that provides access to the rub surface can be used to make this very easy.

Workmanship

Front Strut Rod Bushings

The lower control arm needs to be freed from the knuckle so you can move it rearward to remove the strut rod. The strut rod rubber bushing in the control arm is a bitch to remove without the Ford tool, but can be surgically extracted with lots of foul language and several very sharp X-acto knife blades.

Rear Strut Rod Bushings

Loosen the control arm-to-knuckle bolts so the knuckle can be moved rearward to free the rod.