i've sold my s2 since this, they were BC BR, sorry for the incorrect info originally lol. the new owner tracks his car with the coils and is doing really well. i know heaps who use BCs and love it drift/drag/circuit/street. for entry level track/street performance they are good enough. if you go serious track, dont even bother with KW and go something better. i dont think KW is worth it when a lil bit more you'll get something heaps better.