is the car completely stock? if so , i think your a ways away from upgrading your turbo, there's a few things you can do and dont cost as much to get your hp to the numbers where your going to need a clutch upgrade, then fuel pump,injectors, 3 bar's, then bigger turbo....
imo a bigger turbo or a big wheel upgrade (only) at stock boost levels wont net you as much as a stock turbo with these mods - you have room for 8-12psi gain and 30-80hp gain
FIRST-- get that stock re circulation valve off there asap- its junk, opens at like 4-6psi and bypasses exhaust causing a cluster F of air in your turbo housing causing a surge or "flutter" your probably hear when you let your foot off the gas , get a block off plate -
https://www.ebay.com/itm/SRT-4-SRT4...621035?hash=item2a7121196b:g:yOMAAMXQY8JRhyEf and a BOV KIT-
https://www.ebay.com/itm/Universal-...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649 make sure not to use the vac line going to the stock valve, as its not strong enough to open a aftermarket wg , this will utilize your exhaust into your turbo better and help you spool faster and hold boost longer and better, and will also let boost escape faster when the throttle body is closed thus eliminating or decreasing your surge "flutter" and giving you the loud bov sound everyone loves
NEXT- Cut your stock air box right where the "tube" goes into the "box" this will give you enough tube to fit a cone filter on and give you a makeshift cai and save you around $100 and still net the same "claimed" gains
NEXT- cut off that so called stock "blow thought" muffler.... as it is a blow through yes, but it has small holes through out the inner tube and has 2 nasty bends in the back to the exit in you look down through it, you will definitely hear your turbo from the back way better.... and if you want to go further you can hollow out your catalytic converter cut the pipe right behind it and take a hole tool and drill and drill out the ceramic blocks out then flex tube or get it welded back to the pipe that it was connected to , your turbo will thank you with praise's of loud spools
NEXT- take the money for the turbo and buy a Mopar s1 pcm or DSP handheld (7301) they are both pretty much the same, but i fell the diablo is a little more aggressive, with a tune installed you can bypass your stock boost control valve and hook up a mbc and adjust your boost up to 18-20psi this will put you in the 5.0 Mustang and z28 territory... but dont go past 20psi until you get more supporting mods
Which i will cover here, when 20psi gets boring, get a stage 4 clutch FIRST(stock is only good to about 300whp) set of stage 2 injectors, 3 bar sensors, fuel pump w/ return mod, a stronger wg spring(no need for a "s2 wg" you can make a better one for 1/4 the $ if you just buy a stronger spring and put it in the stock wg) -
https://www.ebay.com/itm/Upgrade-Tu...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649 , after these upgrades you will be ready to get this -
https://www.ebay.com/itm/Neon-srt4-...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
NOW you'll be ready for a solid tune, at this point you should be easily be making 450+hp but i would push it past 500hp until you upgrade your crank and head studs