Just got a 2012 Subaru Legacy question please help!

Hi guys I’m new I have always had really nice
trucks and cars I got really really sick and I
thank god to be alive but because of this my
truck got  repossessed so once I was clear
medically to get back to work I needed a car
I found a 1998 Subaru Forester in
unbelievable condition had 202,000 miles but
it drove so nice I took a chance it lasted me 2
years till I sold it I fell in love with Subaru
since!! I finally got my finances back in order I
could of got brand new but was no need to
do so with me getting married in 8 months I
really always wanted a WRX STI since I test
drove one but I settled with a 2012 Subaru
Legacy 6spd gotta be manual :) and I LOVE it
only has 74,522 thousand miles always taken
care of with that all being said what is driving
me crazy is with it having the 2.5 boxer I was
told by the sales man it’s clearly not going to
have the pick up time of the WRX I test drove
that would of been 405 a month the Legacy
with 90,000 miles less 140 a month I couldn’t
beat it I thought well I can custom the car up
my self but everyone I have talked to says
even though the back bumper has a cut out
for a extra exhaust to not “waste” my money
I was told adding a air intake could mess up
the system in the Subaru so now I’m kinda
upset that I can’t really do anything custom
to the car I really would like it to have a little
more pick up speed I’m in forth gear by
40mph! To me that is crazy I’m not the time
to red line before I shift I shift right at 3 grand
always I will not beat on my car! But after I
get in 4th gear on the highway and I shift at
3grand into 5th I can put the peddle to the
FLOOR the car slowiy like a ant picks up
speed till I shift into 6th gear it’s at almost
2800 in 6th going 65 but again i hit the gas
no pick up if I down shift obviously then it will
pick up speed but it jumps to well over 4
grand and the motor doesn’t sound to like
that very much.... I’m just wondering what I
could do to have just a little more power just
a little more pick up speed I got a after
market tip style muffler was going to have
stock cut out and that installed but every
muffler place I called said “oh you don’t want
to do that! It will sound like a lawnmower and
will give you no extra power” one guy even
said only thing I could do is illegally cut the
hole exhaust out and just have straight pipes
I’ll get a lot of back pressure and banging
down shifting but will add what I’m looking
for I don’t want that sound.... can someone
please please give me some advice on
something I can do after market to just
simply get over 200 horsepower or close to
200 it has 170 stock it’s a beautiful 2012
Subaru Legacy 2.5i sold in 2013 a left over
with real low miles with beating cancer I take
life step by step and LOVE it and I LOVE my
new car in a few years I’ll trade it in and get
my WRX but until then I would like to do
something to give it more power with out
dumping thousands and thousands into the
car any help will be great that you guys so
much great web site sorry for my long text
and my son story I just wanted to explain
why I didn’t get the WRX cause a lot of
answers I’m getting is “you should of just got
the WRX” I just couldn’t I’m restarting my
hole new life heathy and ALIVE I’m sold on
Subaru now I love them any help I would so
greatly appreciate!!! Thank you