I would change the spark plugs and coil boots first thing along with oil and filter change.

Should be more numbers on the tag or a different tag with either
3 73
4 10
4 30
stamped in it somewhere. Or hopefully the rear axle tag will have an L between the first # and last 2 which would mean it is limited slip.
Here is a front axle tag from an Excursion that a friend just picked up at salvage today, it is 4.30.

 

Welcome to the EX forum and family sb1911!
Nice looking wagon with very low miles, hopefully from a salt free area and rust free?
Most EXs from '00 lack the ratio on the door jamb stickers, give those axles another look over to see if there is another tag or more info on the one you saw. Another way to determine if its the more common 3.73 or the optional 4.30 gears is to check the RPMs at 60 MPH. Of course this will work best with stock sized 265/75R16 rubber but the 4.30 gears will have it turning about 2200 RPM at 65 MPH, 3.73 will be just under 2000 RPMs if I recall correctly.
What are your plans for it?
You may want to remove those roof crossbars as they are next to worthless due to how low they are and they can rub the paint off the roof under them, most of us go without them for those reasons.

 

 

Are you familiar with the early V-10 heads and the low number of plug threads, and how folks have dealt with them to reduce the chances of blowing a plug? The factory torque spec for those plugs is a very low 11 ft/lbs, many owners here have increased the torque up to the 24/28 ft/lbs range with very positive results. Whoever replaced all the coils was misguided, they are good until they are not, and that typically is a very long high mileage interval. What you DO want to do is replace the COP's rubber boots whenever you change the plugs, they are a wear item that degrades over time and can bleed voltage out which will eventually lead to a miss.

 

 

Ours with 3.73 gears is doing 2000 RPM at 70 mph.
I pulled our roof rack crossbars off, too.

 

Ours blew the OEM #3 plug at 108k and wasn't towing at the time.
Repaired it with a Timesert kit, definitely do not use a heli coil or similar kit.
We have pulled our 7500 lb trailer thru Oregon a couple of times and have not had any plug problems.
We have 130k on the Excur and 170k on the Exped which has had no problems with the plugs, but I do carry my Timesert kit on long trips.

,

 

Time-sert (sp?) is the leading thread fix for the modular motor's plug holes. Only needs to be done if and when one blows out unless maybe you have the heads off for something else and want to do it then, I would not do it on an assembled motor just for kicks. I would get a good WD hitch with built-in sway control, use a truck scale to get it setup correctly and make a few towing trips to see how it does and then go from there to address any issues revealed.
7,500 lbs of TT shouldn't present too much trouble for a good running V-10 even with the 3.73s, it will slow down on the hills, when it does, let it rev as that's where the power lives in these motors. With the 4.30s they run at slightly higher RPMs and can carry speed better on the hills due to that and the additional ratio.
My EX no longer sees any daily driving duty, it now serves us as the dedicated tow vehicle for our 41' 11,300lb (min, about 12K for longer trips) TT where it performs very well all over the Eastern states. Originally it pulled our old 9,500lb TH for about 15,000 miles while I performed most of it's mods and it kept getting better at the heavy work, in totally stock form with 3.73s it would downshift if it ran over a shadow. It has now pulled the current big TT for about 27,000 miles in it's current configuration.
All stock with the TH it used to get 6/7 MPG towing on a mostly flat route, with a change to 4.88s while still turning the same 32" tires it got 9 MPG over the same route at the same speeds towing the same trailer and it didn't downshift a single time on the highway portion of that trip (to/from Philly/Savannah). Now with the 4.88s, 35" tires, Banks headers and Y pipe, Aeroturbine 3030XL muffler and 5Star Tuning's 89 Octane Performance tune it regularly gets 8 to 9 MPG on mostly highway trips towing the TT with a best yet of 9.5 MPG over a 420 mile trip. On a rare unloaded trip last Summer it got 14.5 MPG over 490 miles with the cruise set at 65 MPH the entire way with the AC on about half the trip. Rolling at 19,000+ lbs combined it can maintain 55+ MPH on most Eastern Interstate Highway grades while holding OD.
From my experience the single biggest performance and towing mod for these V-10s is deeper gears and my second pick would be good custom tunes, like those from forum sponsor 5Star Tuning.
If you plan to change the plugs soon for piece of mind read up on the procedure up in the great Tech Folder at the top of this EX forum page first.
Plugs are Motorcraft SP-479
Boots are Denso #671-0001 (set of 10). Denso is the OEM manufacture for Motorcraft and are about half the cost of MC for the EXACT same parts.
Cops are Denso #673-6000. Maybe pick up 1 or 2 to have on hand as spares if one fails, I have had my 2 riding along for a couple of years now unused.
To make the change a little easier the GearWrench #80546 5/8" X 6" swivel plug socket works great.

 

with 265/70r18's on my V10 and 4.30LS gearing i am turning around 2400rpm indicated at 75, this info may or may not help you. my tires are 1" taller than stock at 32.6"

 

My opinion on performance upgrades in order.

1) cool intake charge via water meth. IAT at valves is about 50 degrees less than the coolant temp due to the large intake system. So, iat is around 130 degrees at valves. More in hot weather. This mod is good for over 30 hp, as the methanol adds fuel and cooling, which prevents knock and keeps knock sensor from retarding timing....which means more power.

2) 5 star tune for transmission and to lower power band rpm torque curve.

3) add performance valve bodies in transmission.

4) add a torque converter that is designed for the use of the vehicle.

5) gears

Don't spend $$ on exhaust it's a waste, for any rpm under 3500. If your running WOT alot than ok bigger better flowing exhaust is ok but under 3500 rpm the stock exhaust is way good.