Not really built in a sense that it was straight cut gears or anything. But I would have to say a lot more built that compared to others. The transmission was completed taken apart, re-fitted with new syncros, seals, and bearings. The bearing from the rebuild kit are nice, cause they are new, but thats all they are good for. I have seen the bearing get smashed. So I took all the bearing and contact a bearing truck company to see if they had some heavy duty ones that would match. They were able to match all of them up for heavy duty bearings. The thrust washer was re-made in titanium and everything that was made of metal was cryo-treated, including the casing to the transmission. The clutch fork was also re-made from CNC machined aluminum. So far the transmission has been put through a lot of abuse and nothing has broken. I noticed that the transmission going from first to second is knotchy, yet exact and you can down shift with no problems. I told the transmission guy to rebuild the transmission with good tight tolerances and I think that made a great deal of difference. That is about it, I have dropped the clutch in at 5k for burnout and such and the transmission holds. I think everyone that want to rebuild there R154 should do it this way, if you build it, it should be built right the first time. I personally dont want to go this route, thus my project, I'm going with the Solstice Transmission which is nearly identical but it my opinion much better than our old 80's transmission cause refinements have been made on that transmission since ours came out.