well there's a way of telling which trim model you have.

first off, look on the back of your car. if, on the passenger side, it has a DOHC VTEC badge, then that means you have a GSR. If it has a Special Edition badge, then you have an SE (Special Edition...lol), if you have drum brakes on the back, then you have an RS. if you have disc brakes on the back and no Special Edition or DOHC VTEC badges, then you have a GS or an LS (could someone clarify on the differences between the GS and the LS?).

as for deciding whether to start with the engine or the suspension (you're a good man for not being able to decide between these two...most ppl are like omfg intake header exhaust all the way bro and don't consider the suspension until they want their car to be lower...kinda gets to me sometimes...), I say drive the car for at least a month (the more time the merrier) and see what aspect of the car you'd like to see improve, then upgrade some parts accordingly.

hope this helps!