just wondering

what kind of mods besides an exhaust system, cold air intake and new throttle body that are relatively inexpensive can i put on my 4.6 to boost hp? any thoughts or suggestions?

the simplest and least expensive thing you can do is get a set of underdrive pulleys from March (which is great, because you're just freeing up existing horsepower from the accessories). In addition to the March Pulley Kit (Alt, Crank, WP), get a Ford Racing 5.0 Pulley Kit (A/C, PS), which will fit. Each kit is between $100-175 respectively.

Hold off on the throttle body until you get a module/programmer, instead get a set of hi-flow headers from JBA in SoCal or Ford Racing (there are others, just research-expect $100-250). After you have a module (Hypertech, SuperChips, etc) THEN get a larger throttle body and Mass Air Flow meter (gotta program them to work). I recommend BBK and C&L for their TBs/MAFs (the SVO stuff is the same size as stock).

A good FREE way to free up HP is remove air intake silencer from airbox, in the wheel well (expect 2-4 HP). Can get better using dryer tube ducting for "home made" Ram-Air of sorts, running from lower Passenger side vent in airdam up to the airbox (usually 5-6 HP at that point). Not much, but its free and easy to do, just requires time. Horse Power Alternatives would be things like a B&M/TransGo trans shift kit, steeper gear ratio (at least 3:55:1, 3:73, or 4:10; stock = 3:27), or even a better rated tire like a radial T/A well help get you their quicker. Your best bang is no doubt a Module/Programmer, if you have a computer, just punch in a few keys and BAM! instant power. Hope that helps.