I would figure out what your looking for first. I did alot to my se over a 4yr period because it gets expensive.
1st for the svt look I bought from ford the svt front/rear bumper covers, side skirts, all the grilles and brackets cost me well over $1200 before paint.
E1 wheels and tires about $900 new used maybe $250 and up.
so far roughly $2500 for kit, wheels and paint.
for the motor I did svt uim, optimized TB, injen intake, ford racing 9mm wires, jet hot headers, magnaflow hi-flo cat, resinator and dual mufflers with 2.5 piping. full dyno tune on a dynojet dyno and went from 124 hp to 156hp at the wheels after static loss comes out roughly to 190hp. My timing and fuel curves are set up for when I put my zex kit in. I'll use a 75hp shot which willl net me around 265hp with the shot.
I was't looking to make my se an svt but I do love the svt's looks so that's what I went for and modified my se to make it a better se. I believe with a some money and time you can make a real nice se with the svt look. You can get power from your 2.5 and get it close to a svt's w/o a 3ltr swap unless that's what you want. I left the interior alone because again I wanted to make a better se with the svt looks.
remeber in the end you will have a better se but your not going to have an svt(if that makes any sense 
) If that's not what your looking for then the others are right, just get an svt. hope this helps you get pointed in some direction.
