installation depends on the shop, and the materials used to-- so some shops might be more/less then that.
for the cig. adapter-- there are some that might work, but all of them are not universal in the sense that you just pick a random one up and it will work. you need to match the power requirements, output voltage of the adapter, and input voltage of the device.
also, i am not sure how sensitive the fit2pc is, but most computer devices want tightly regulated power(ie: they don't want to see 12v fluctuate more than 0.1-0.3 volts..) that most cig. adapters usually don't do
Fit-pc accepts voltages from 8V to 12V; that's one of the listed features: smart voltage recognition within that threshold.