if you want to make power in the 1.9, i have to ask how much money you want to spend on it?
for max power, swap to a 2.0 SPI and then proceed with my suggestions. I kept the 1.9 for my 91 Pony.
just the SPI intake manny wont work with your engine, the throttle body off of one is a nice upgrade and is 4mm larger.
go find an old 1.9 HO and get the 4-2-1 header from it. fit it to your car. it'll hang a little low, but its generally ok.
then go get a new exhaust pipe ran, 2" is good, 2 1/4" if youre going to have head work done.
buy the 25% underdrive pulley for the SPI from
www.blackdiamondracing.com. by the calculations it is supposed to add 7.8hp to the crank.
if you have about $700 burning a hole in your pocket, have your head (or a spare) pocket ported, smooth out the valve throats, unshroud the valves, minimum 3 angle valve grind, port the intake and exhaust side.
if you have another couple hundred laying around and feel like adding another 10-15hp on top of the 20-30 the ehad work just got you, you can toss in a new camshaft, id suggest Crane. they have 3 upgrades for our engine.
with the cam use some double valve springs for the 2.3 turbo ford.. they work great as i have them in my 91 1.9 pony. new lifters are a MUST here.
i'll assume you already put on some sort of intake or whatnot..its kinda a basic thing to do, and if you havent done it at this point, its the restriction in the entire engine system.. so get rid of the stocker and get something better.
to go with that new cam, you may want to buy the adjustable cam gear from blackdiamond as well.. its 125 well spent.
and that my friends, is how you make power in the 1.9. (well, its how you start anyways.)