Silver,
All of the CSX's were Black on silver and only made in 87.
in 88, the CSX-T's were white on silver and only made in 88.
in 89 the CSX-VNT were all red and only made in 89.
the 90 CSX was going to be blue and feature a DOHC 16-valve turbo motor (pre-production Spirit R/T/IROC R/T pieces) and driver adjustable suspension.
Looks like repainting the bottom half silver and adding some decals from Dave Salamone at Positive Impressions should get you very close to a proper 87 CSX (or he can cut vinyl in any style you'd like, he did Shelby stripes in Wood for the Mini-Me guys for the first or second Challenge).
There's a place in Texas that does steering wheel upholstery for the LeCarra style wheel that came in these cars. In the meantime, they use an old larger bolt pattern Momo/LeCarra steering wheel so you can swap the wheel out and wait for the proper one to be repaired with an adapter ring or an older wheel. I've seen LeCarra knock-offs on eBay for cheap. There have been some that stripped the black paint off their wheels and polished the aluminum, which I think could look pretty good.
Oh and polish up the wheels to a mirror finish and represent the 80's in style!
The T1 bottom end is plenty strong once the lightweight rods are tossed for the forged units that came on the 87 Daytona Shelby's (one of the reasons Shelby eventually left Dodge was this sort of BS where his cars went first then Dodge came out with a similar product with better parts) The cast crank is good to upwards of 300hp before the block starts to let things down. 4-bolt mains or a later model (89+) block helps reduce the block flex.
The main improvement on the 87 and later HD turbo blocks was the cross drilled coolant passages between the middle cylinders on both the block and the head. This lowers the temp at the HG by about 70 degrees and improves longevity. Not exactly critical, but if you have a choice, this is the direction I'd go in. After 1989, all of the engine blocks and heads were supposed to be cross-drilled, many weren't as it was a running change.
Transaxle's aren't bad and are essentially the same as 1st-gen Neon's internally. later A523/568's are nice if you can find them, but the 520 with good oil and a fresh rebuild, a bearing retainer plate and a limited slip will work pretty well. Spirit R/T clutch kits work to upwards of 280hp, but depending on the transmission you use may need a different clutch disc.
Automatics suck on the freeway or around town, but they are a ton of fun on the AutoX and at the strip. The ability to build boost on the line with an automatic is damned handy for getting out of the hole and the ability to build boost before you exit a corner while left-foot braking is much easier in an automatic. The trade-off being that the the automatic requires a good amount of power to run and weighs quite a bit.
Core supports on the P-body's were notorious for failing at the spot welds at the forward frame rails. Break out the grinder and the welder to fix this and the panels that support the strut towers along with the firewall. I had a CSX-T IMSA SS car that eventually cracked the firewall before I got it third-hand. Another IMSA road racer fixed this early on with his race car by installing a second firewall skin.
Later model cars had slightly better suspension geometry and some had 11" brakes, cheap and easy upgrade to do. If you have a friend that is good at machine work, a set of balljoint extenders can help correct geometry issues after lowering the car. Cheap coil-over sleeves aren't a problem and as I discovered the other day, the struts on a 924 are nearly the same as Shelby-Dodge as I used the Advance Design struts my Uncle used on his car on my 924 after adapting the 924 top hat to the strut (not surprising, the 924 and 944 use mostly Mk1 Rabbit front suspension).
Rear suspension is standard beam axle. Rebuild the panhard rod to be stronger and adjustable, then add a 2"x36"x1/4" steel plate to the bottom of the axle to stiffen it up. Use HD muffler clamps to hold it in place and to make it adjustable (you can add/remove clamps or change their position) If you're really skilled, you can make the panhard rod/track bar mount adjustable and install weight jackers/adjustable spring seats on the rear.
Welcome to the wide wonderful world of Shelby-Dodge!
I did buy some parts from him for $100, including some interior stuff, new front rotors, a set of used calipers, a new e-brake cable, spare injectors, a broken fuel rail (apparently they are hard to find) and a new upgraded clutch kit. Not a bad deal if you ask me. 
I'll try again:
