The kit is manufactured by Prothane and was originally distributed exclusively by High & Tight Motorsports. Urethane suspension bushings are considered by many people to be the best upgrade you can do for your car's handling.

WILL I LOSE RIDE QUALITY? The original rubber bushing was fairly soft, which helped attenuate noise and vibration that is generated by the tires and road surface. Increasing the hardness of the bushings either with harder rubber, urethane, or even bronze will allow more transmission of noise and vibrations. Some manufacturers formulate the hardness and design to reduce this effect. A softer urethane bushing allows the vehicle to perform better without the harshness, even over rubber components of the same hardness. The only change in ride quality is increased performance. This is why the Prothane total kit is a better choice than TRD bushings.
WHY USE URETHANE? Factory supplied rubber components are on the soft side to accommodate the typical car buyer. They tend to deteriorate very rapidly and, since the MR2 is now in it's 16th year, the OEM rubber bushings have long since lost their effectiveness. Most MK1's now suffer from "spongy" and less than ideal handling. Urethane will correct these conditions while improving drivability and ride quality.
DOES URETHANE SQUEAK? In a word, NO! Squeaking is caused by high frequency vibrations that can be heard rather than felt. It is usually caused by lack of lubrication, poor installation, incorrect part, or urethane that may be too hard for the application. In sway bar mount applications, most squeaking is the result of not cleaning the bar thoroughly prior to installation and failing to use the supplied "squeak proof" Super Grease. Additionally, the MR2 bushings were manufactured with grooves and channels to hold the Super Grease to provide long-lasting performance.

If you’ve added aftermarket springs and struts, but still rely on OEM rubber bushings, you have not yet realized the full potential of your upgraded suspension components. Normally, the addition of urethane bushings improved handling but compromised ride quality. This is not the case with the HT urethane bushing kit. In fact, you’ll be pleasantly surprised to find that we’ve actually been able to achieve the elusive delicate balance of go-kart handling without the bone jarring ride commonly associated with urethane bushings. This is because urethane bushings allow your strut dampers to absorb the shock normally absorbed by your old rubber bushings.

The result is a firmer, sportier suspension, without compromising ride quality