Well your opening up a big subject here.First the spoon motors,as nice as they are are a waste.You are doing just as good with the B18C5 and some mods,for less.For 2000 ex IMO,your best felt difference is going to be a B18C1 or B18C5 or a ls/vtec frank. because it is a heavy car and you'll be happier than if you go with the B16A2 that the si's come with.For cheap mods,start with the basic's I/H/E and maybe a small dose of nitrous for the added thrill.The intake and exhaust will be able to be used on your swapped motor,but the header won't be (I don't think the D series headers will transfer to the B but it seems like I read this somewhere).You can advance your timing,but it won't yeild a whole lot,and you need to be careful doing it.You can go the H22 route also.It will wind up being a little more than the B18C1 price wise,after installation,but the gains are nice.