Hi,
That's interesting, I thought all ST200s had full leather, and the ST24s half leather. I think only the cars with recaro full leather were the limited edition saloons.
The options do vary a bit on ST24s as early cars 97/98 seem to me to be based on Ghia Xs, so can have more but then Ford obviously realised they could build them to a price, so later ST24s 99/00, of which mine is one, had subtle differences.
As for getting more grunt, my best 2 bits were a KN 57i induction filter (8 bhp) and decat pipe (about 10bhp). On the ST200, don't bother with an induction kit as too much heat and people have had problems with them, for the 200 best bet fit a KN etc panel filter in the original box. Some people have added extra cold air feeds on ST24 to the induction filter and on the ST200 extra cold air feed into the original filter box.
The decat pipe is a great mod, and should be OK for emissions at MOT as you still have the 2 precats, mines been thru 2 MOTs fine. If you get a decat pipe, just be sure you get the right end fixings, I know of 3 different types of end fixing depending on year of the car, that's why it took me ages to find mine, or if you get one made up then you will have no trouble.
Also, don't think changing to aftermarket exhaust will get you more power it won't, as I found out when on rolling road day, someone who just got new Ford exhaust fitted got same output as mine, which has twin exit system on it, but I prefer my twin pipe system, makes car look better in my opinion.
Apologies for prattling on, but hopefully useful info.