Well, if it's the "all new" spectra, you have a 4cyl 2.0 beta II engine -- seeing how I don't know how much the car weighs... hmm... if it's a manual, your looking at mid/high 16's with just a Intake... if it's a auto, your looking at high 16's to mid 17's...

If it's the regular Spectra your (4cyl 1.8 beta engine) your increase the above times by a second

Without a turbo in either engine, your not going to see anything lower than a 15 (thats after craploads of N/A work done to it) -- or the other option is just start sprayin the 2.0 engine handles a pretty decent sized spray easily...