O.K., I got curious and did some digging around.
The Tracer is the same car as a Ford Escort; you can try to see if older parts, no farther than '92 will fit.
K&N makes an in box air filter for it. (And most any other car)
At
http://www.truckperformance.com (The place is not just for trucks) I found a Jet Power control unit for about $195 to re-program the ECU.
Also found a Monza cat-back exhaust (On sale for $208.99) for a '93 Escort (My old car); don't know if it will fit a 4-door, but the floor pan of the car did not change (Except the wagon) so it should fit.
Also listed for the '93 single cam 1.9 (Same family of motor except on the intake side and computer as '97 & up): VENOM nitrous kits and fuel pumps!; Nology plug wires (They will fit); Lowering springs; Ractive front strut tie bar; Energy suspension bushings; camber kits (Not for wagon); short throw shifters; Lightweight flywheel (Don't know if still available); and a Pacesetter header kit (Don't know if it will work with the newer OBDII computer, '97 and up).
Had to look under Ford Escort for all parts though. Nothing else besides that. Can't believe I found as much as I did!
It is possible to swap in the 2.0 Zetec motor from a Ford Escort ZX2 (Later ones prefered; same motor as Focus ZX3; called only "ZX2"); that would open up posibilities a lot more. Not to mention a LOT more power. Would only be worth it if you can get it dirt cheap; maybe out of a totaled ZX2.
I've seen things done to Escorts though; most of it custom or a kit ment for something else tweaked to fit. There are forum sites out there on the net for Escort owners that might know more resources.
Have fun. Later.