Are you planning on installing it yourself? If so, just surf around and look for the best price. If not, look around your area for autmotive specialty shops that sell the type of alarm you are wanting to get.
__________________
2006 Mustang GT in Torch Red
C&L Intake, Evolution Performance Tune, Borla Axle Backs, Hurst Shifter, 4.10's, JBA Long Tubes, Prothane Engine Mounts, Steeda UDPs, FRPP Charge Motion Delete Plates
search for the one you want then go to ebay to buy it. just be careful and read the WHOLE auction. and if its to good to be true it probably is
__________________
89 hatch lx four inch cowl hood.
trick flow intake, bbk 80mm tb, bbk cai, grannatteli maf, b cam, electric water pump, aluminum radiator, electric fan, pulleys, a/c and p/s delete, bbk long tubes, H pipe, 40 series flows, msd 6al, ford racing 9mm wires, msd cap and rotor.
t-5 tranny, alum. drive shaft, tubular control arms, air ride launch kit, bbk lowering springs, weld drag lites, subframes
florida 5.0 guage cluster w/ autometer carbon guages, race buckets, pro 5.0 shorty
best place to buy an alarm sys 
