cheapest intake would be the napa 6637 part number with a little chunk of 4" exhaust pipe, check that mod out in the 7.3 area of the tech section, TW and DP are the top 2 7.3L tuners around it seems, most reccomend you get gauges first (EGT and trans temp if you have an auto) just so you don't hurt the motor if you start to over endulge on the power, which can happen when you get a chip that almost doubles your HP and adds more then 50% additional torque.