1. Serpent S120 LTX ... good car to buy
2. 1/F is this hobby shop: http://rc-evo.com/xbbs/forum.php?mod=forumdisplay&fid=82
(address is in RED)
3. elastic band is only for older CRC cars, Serpent cars cannot use the elastic band method unless you modify the car.
However, if you go this route, you have to use 2s lipo (7.4v) because I think older esc's can only operate between 4.8v to 9.6v.
Please note that 2s short lipo is thicker than 1s short lipo. I dont know if s120 LTX can fit a 2s lipo or not.
(2s lipo is about 25mm thick while 1s lipo is about 18mm thick) Maybe another c-hing can answer this question.
FYI: I play s120 link (older version) with 2s lipo and I need to raise the center antenna/shock holder by 2mm and the rear shock connector by 2mm to fit the thicker battery. I will take a photo tomorrow for your reference.