Re: What should i spend my last bit of money on...
One thing we always hear about these is they are hard on batteries and the electrical system in general. By far the best thing I have done to keep my voltages stable under any condition was a three-way electrical upgrade. First, and probably foremost, is get a GOOD HO alternator. Not one of these ebay knockoffs. Look up car stereo alternators...GP, Mechman, Apex, and so on. If you have stock electrical draws (no upgraded stereo or lots of fog lights, etc) then I would probably get a 180 amp alt minimum. I have a 250 amp, but I also have a sound system...and it's not big enough. lol Along with that alternator, you're going to need to find a shorter belt. These come with smaller pulleys so you get increased output at idle.
The next thing you'll want to do is what's called the Big-3 or Big-4 (depending on what you do exactly). This is essentially adding in more wiring for your batteries and alternator to make sure you're actually going to get that 180 and up amps out of it. The stock size wire coming from the alternator is NOT going to cut it for an HO alt. You will want some 2/0 copper wire (you don't want CCA...and despite what people claim, it doesn't have to be rated OFC), lugs for the ends (make sure they're tinned!), a crimper for the lugs (can get em for cheap on ebay and they work great), and a fuse holder with fuse rated just over what your new alternator is rated for. Even though you already have stock connections, run a wire from the negative of one battery to the negative of the other. Do the same for the positive. Next, run a wire from the negative on the passenger side battery to the alternator casing (most HO alts have a bolt post for this), and/or run a new ground wire to the engine block. Finally, for the alternator output, leave the stock wire in place and add in your own with that fuse in-line. You now have a robust charging system, but you're not done.
If you have standard lead-acid batteries it may be time to upgrade depending on how old they are. Look into getting an AGM battery. It's still lead-acid, but it's sealed, has a higher rate of charge/discharge, can withstand more abuse, etc. When I swapped over I noticed an improvement immediately in how well she started up in the morning, and how little voltage drop I would get when my subwoofers were hitting hard. If you decide to go with AGMs, don't fall for the hype and get some fancy uber name brand like an Optima or a Northstar, etc. A Duralast, SuperStart, or whatever the big parts store brand is these days will be just fine. I can't remember where the thread is on here, but a while back someone did a lot of digging to find out that there are only like four major battery manufacturers, and more often than not the same exact battery is just re-branded and sold for a different price.
You can do all this for less than the $1,000 you have left. It doesn't sound like much, but the benefit will be much farther reaching than you can imagine. Anyway, just my 2 cents.
2004 Excursion 6.0
New HPOP/HPO system o-rings; Updated standpipes and dummy plugs
EGR delete; Rebuilt oil cooler; CCV collection mod
VR Black Diamond head gaskets and ARP studs
Oil and coolant bypass filters; Shell EC-1 coolant
Rebuilt turbo; 250 amp alt; 6000 watts of brain scrambling
One giant 240 pound English Mastiff riding shotgun!