Hi and welcome to mightyram. First is ID'ing your engine - die cast timing cover or plastic? If it's die cast it will either be a 4G52 (2 litre Astron) or 4G54 (2.6 litre Astron). Plastic timing cover will denote it as being a 4G63 2 litre Sirius engine. There should be a metal plaque on the firewall directly behind the valve cover with the info on it. Camoit has gotten together with DG Headers to make some really nice headers for the 4G63/64 engines - add a Weber, delete the emissions crap, some mild port work and a good tune up and it'll haul.