In Sheep's Clothing

So I just bought a 2003 Mustang GT Convertible 5 speed with a Borla Catback exhaust. This is my first Mustang and I'm enjoying it so far. My previous two cars were a 2009 Subaru Legacy GT that was just north of 250 hp and a 2005 Legacy GT that was pushing 310 hp plus both of which are now totaled. I know a little about Mustangs, enough to hold my own in a casual conversation but not too much more. I knew the world of Subaru well and had a firm grasp on the mod progression that would normally follow.

I know one of the first things on my list is a tuner. I was looking into an intake, some added exhaust work, and for the love of God a short throw shifter. I'm not sure which way to run brand wise with any of these mods and was hope for suggestions. I'm excited to see what the car can do and learning a whole new world of modifications.

-ISC

Luke13

One of my personal favorite places to get parts and guidance is Americanmuscle.com and these forums of course!! American muscle has a great selection of parts, install write ups, and competitive prices. As far as brands go, you'll eventually find a brand you like and go with it. I've been a fan of BBK parts, but sometimes you can get off brand stuff that'll do the exact same thing. Just research each part you're looking at upgrading. Check out the sticky threads for some good starting points. Good luck, and welcome!!

SyNdicateZ

Wait, how did BOTH your subarus get totaled? Wife?

agarr19

welcome ! i went away from my first mustang to buy a 2011 WRX had it for a year and a half before i came back to mustangs haha your gunna love it

school boy

heres a nice little how to section to get you started;
https://mustangforums.com/forum/4-6l...ted-often.html
welcome to the forums!

In Sheep's Clothing

Well they didn't get totaled at the same time. The 09 got totaled in August of 2012 and then I bought the 05 a week after that, then promptly totaled it 6 months later.

Sonic Mustang

I am not a big believer in "canned" tunes. I lightly modified my car with an SLP Loudmouth catback exhaust and a C&L intake system and had it dyno tuned along with two other 2004 Mach1s with exactly the same modifications. Initial readings showed two cars running slightly lean and one running slightly rich. I saw this first hand at Swanson Performance. (Danny Swanson is one of the top Ford tuners in Southern California.)

Mach 1s have GT convertible subframe connectors installed at the factory. They are not so strong bolts ons. I replaced mine with Maximum Motorsports full length welded on connectors and the increase in chassis rigidity was very noticeable. It will be even bigger on a convertible. I also have H&R SuperSport Springs and Tokico Illumina adjustable struts/shocks along with Maximum Motorsports caster/camber plates and height adjustable rear lower control arms.

Maximum Motorsports makes some of the best Mustang chassis components and I would suggest the same set up for your convertible - I've driven a 2002 convertible set up like my car and the difference from stock was night and day.

I would recommend Bilstien shocks instead of Tokicos. Over the years, warranty replacements were no problem, but since Tokico was purchased by Hitachi, things have changed. When I tried getting a warranty replacement, I was told I had to go to the dealer who sold the shocks (in my case, out of business) and have him return it for WHOLESALE credit and I would be responsible for the retail price difference. I had to spend over an hour on the phone to get Tokico to replace the shock directly at no cost. Never again.

Check the Technical Service Bullitens on the Tremec 3650 5 speed. The correct fill is now 3.0 liters instead of 3.8 liters.

There are several choices for short shifters. I've been running a Steeda Tri Ax with excellent results and hear good things about MGWs. Do not use the shift stops in any short shifter on the Tremec 3650. The transmission has its own internal stops and misadjusting the shifter stops could prevent the trans from engaging gears fully and result in damage.

The two best places for information on modifying your Mustang are Maximum Motorsports and MRT. (MRT isowned by Scott Hoag who was the Ford Program Manager for the 2001 Bullitt and 2003-2004 Mach1).

02blkkb

I just bought an 02 gt kb supercharged. The king cobra clutch in it is super super stiff. My leg is actually sore from driving it yesterday. I've heard the centerforce clutch can handle over 400hp and remains the stock feel. Sorry to hijack, thought it might pertain to your original post since you wanna mod your stang OP.

Stevo86

OP, aside from checking out school boy's link...

Don't worry about the intake, unless you plan on some heavy mods as in cams, head job etc, you won't get anything. Throttle body and upper plenum are a good start but honestly you will feel the most gain from a new set of gears. The stock 3.27s are just not where it's at. Get some 3.73s and go from there.

03machab

Gears mid pipe tuner. That I think would really make the car feel completely different for ya!!