K-member Qs

so what is the advantages to putting in an aftermarket k-member, other than weight reduction. it moves the engine back an inch for most kits. does that mean that it moves the shifter back an inch? have to get a smaller driveshaft? the car is mostly for street, but goes to the track. not a corner carver. is it worth getting?

i was lookin into Griggs k-member kit. i know griggs is the like the best in the business. any of you guys have it? opinions?