Toshiba America Inc yesterday unveiled the T3100e enhanced successor to the 80286-based T3100/20 laptop, saying that at 12.8 lbs, the $4,300 system is more than 2 lbs lighter than its predecessor. Compared with its predecessor, it has faster processor and disk, larger memory, co-processor support, higher capacity floppy and additional serial port; a dual-fun ction slot takes an IBM 8-bit half card as well as a 16-bit Toshiba.