simple answer, i recommend it. carbon buildup is broken up by seafoam, thus the need for changing fluids/filters. i have noticed better gas mileage, up to 4 mpg at 60-70mph. i'd add the seafoam to the crankcase and fuel at once, then into the intake because you're gonna need to drive the car pretty hard to get to all the nooks n crannies of the intake. don't be worried if your car doesn't smoke a ton, it means you're harder on the car than someone takin' it easy, with a result of less carbon buildup.
when seafoam is added to the crankcase, sludge preventing leaks from your gaskets may get broken up, so i'd change the VC gaskets(if they're stock). an oil change/filter is highly recommended within 200 miles.
when added to fuel, i like to let the tank get down to 2 gallons or so before adding seafoam, so that the seafoam to fuel ratio is higher. this will clean out your injectors. i've heard of replacing the fuel filter once the solution has been completely ran through, but i don't think it's necessary.
when added to the intake(the smoke part), i like to use the brake booster vac line, but any vac line leading to the intake works. add about half of the amount you are putting into the intake slowly and then at once pour the second half in and your engine should stall. hook your vac line back up and take 'er for a helluva ride!