Upgrade Advice on an 89 GT Convertible NJ

SteakDad

New Member
Apr 17, 2025
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New Jersey
Hey guys, I just purchased a 1989 Mustang GT convertible, 83k miles 5 Speed Manual. This is technically my second Mustang, as a teen I had a 1995 GT Convertible which was actually my first car. Back then had that shiny new model, but always liked the foxbody better.

Anyway. I just received the car and am in the process of planning sound system and basic performance upgrades. This 89 is 100% OEM stock, all original body panels. All of the little touches under the hood to look for that you may expect are there. This was a 1 owner Arizona to California car so there is little rust other than a little surface rust. It has not been modified in any way whatsoever.

The goal is to maintain a stock appearance with the exception of likely moving to a 16" or 17" wheels from the factory 15". I am not concerned with "how fast" the car is. This is a jersey shore cruiser to me. Performance upgrade outside of that exhaust note are for drivability not speed.

A couple initial driving impressions. A little grinding occasionally going into 2nd gear and reverse. The suspension feels a bit worn out, I am not confident that the vehicle would handle well at high speeds. The sound system is shot all together and needs to be replaced.

Things that I know I am going to do...
1. Full speaker replacement with a 4 channel amp, plus a powered subwoofer and a double din head unit.
2. Two chamber flow master exhaust likely just CAT back (had those back in 1995 and its the sound I need to hear today)
3. Get the suspension fixed factory stock or with a modern upgrade.
4. The previous owner did a lot of bad touch up paint on the car, so I need to either repaint or possibly just wrap it
5. Fix a lot of the weatherstipping issues (The car is 36 years old)
6. K&N Drop in Filter
7. Fix whatever is going on with the grinding in transmission

The questions that I am seeking your assistance on are as follows.

1. What upgrades are considered to increase the value of the car, or at least not diminish the value of the car?
2. For a rare untouched all original vehicle like this, if I were to repaint even factory color, does this hurt the value? Or should I just fix the smoothness of the defect areas and just wrap the car a standard white like it is now?
3. Can I switch to a suspension like Maximum Motorsports and not ruin the value of the car?
4. What additional upgrades can I do that do not affect the value of an all original car?
5. Does it make sense to do a header back exhaust? What effect on originality value.


I know I'm all over the place here. But the goal is to make the car drive, sound better but not reduce its value with "speed" upgrades.

Finally. I am looking for a foxbody expert in NJ preferably norther NJ, Passaic, Morris, Essex, Bergen county area that just know what to do with this car based on my expectations. Really looking for recommendations please.

Thanks Alot!
 
 
First off make a plan...... Then research and ask us questions.
My questions to you are how are the roads in your area and what's the budget?
I may be a little different than most members here (duh!!) I want a 'sports car' (best I can describe) driver and don't care too much about shiny paint.
 
First off make a plan...... Then research and ask us questions.
My questions to you are how are the roads in your area and what's the budget?
I may be a little different than most members here (duh!!) I want a 'sports car' (best I can describe) driver and don't care too much about shiny paint.
I’m in NJ but this car likely just cruising in the summer. It won’t be out in salt roads etc…. Will be garage kept. I realize there are some hard core people here that are all about 1/4 mile times. Not me. I’m putting kids in the backseat and I just want them to experience a bit of what it was like cruising the Jersey shore when I was a kid. And as far as having a hard core sports car, I have other cars for that. Goal is to get the car to ride like a modern car, have the legendary exhaust sound we are all used to, and be restored as best as possible. In all honesty I may go for a hatchback down the road and modify that.
 
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Well you're just like the average member here, I don't care when you drive your junk, as long a you drive it.
Sub frame connectors, strut tower to cowel brace, good shocks and decent tires, buckle up the brats in the back, top down and you're cruise'n! :nice:
Get a roller to modify, you'll thank me later.
 
If you want it to ride like a modern car then put an SLA front suspension in it and if you have the inclination, time and money an IRS in the rear. I am not saying it cannot ride well with the McPherson front suspension and the solid axle in the rear but the difference it night and day.
 
All new shocks, quad shocks and struts (Monroe, OEM replacement)
All New suspension Springs
All new suspension and body bushings (rubber, no urethane)
Quality set of Lower control arms
Subframe Connectors
All New Wheel bearings, calipers, rotors, drums, and pads (OEM, no craziness)
If the heater core is original, replace it
Consider a 17 inch wheel, it will be easier to get tires for

Just about any suspension mod you could make on a Fox is going to make the ride more harsh with [few] exceptions.

The stock suspension on the Fox works very well for a cruiser. It was [always] a compromise between comfort and handling.

Most folks here (myself included) are used to doubling or even tripling stock power levels... Those kinds of upgrades just aren't necessary IMO.
 
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If you are going to consider new wheels then give serious thought to converting to the car to five lug with SN95 parts. Hige wheel selection and the SN95 brakes are 100 times better.
 
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