You bet they are. After going thru 4 re-built starters to get one good one on a previous car I decided to try one of the high performance models. I ordered it from one of the speed catalogs. It was $159.00 verses the $45.00 lifetime guaranteed model. This starter has all new parts, ball bearings instead of bushings, a 4 to 1 ratio that starts the car so fast, I just bump the key and the engine is running, its half the size and weight of the stock starter. I am very happy with it and recommend it over the re-built units any day. Has anyone else had any experience with these good or bad you would like to share?