I assume your standard mitsubishi mirage wheel size was 13x5.5 running a 175/70 r13 tire, this gives it a rolling diameter of 576mm, standard offset is 46P with a tire diameter section width of 177mm, so the the plus 44P offset of your new 17" wheel you are talking about is only a 2 mm variance from the standard offset of 46p, so no problems so far with offset
The 17"x 7.5 wide rim fitted with a 215/40- 17 inch tire will have a rolling diameter of 604 mm with a tire width of 218 mm
If you use a 205/40 17" tire instead of the 215, you will have a rolling diameter of 596 mm with a tire section width of 212 mm
If you use the 215/40 tires you will be increasing you overall rolling diameter by 22 mm and tire section width by 41 mm, this will result in your speedo showing aprox 105 kph when you are really doing 100 kph.
If you use the 205/40 tires you will be increasing your overall diameter by only 20mm and tire section width by 35mm, this will result in your speedo showing aprox 104 kph when you are really doing 100 kph
So on those above figures the speedo should read about 4-5 kph higher than what you are actually doing (better than reading slower i guess) and the 205/40 should be legal (dia wise only) with the 215/40 are a problem at 41 over standard rolling diameter, but the only worry i see is the section width increase of each of the tires over standard of 41 mm and 35 mm respectively for guard clearance.
Like you said "Guards are rolled and bumper tabs are gone" so yes both should fit, but the 205/40 - 17 will be within legal rolling diameter parameters and may actually be a better fit under the rolled guards as they will be 6mm narrower under your wheel arches than the 215's.
While the "rolling diameter" of the 205/40-17's will be within legal stats, the increase in rim width over standard of 75mm may be a problem, in qld i think its at 12.5 mm over standard track last time i read it years ago.
I don't know what state you are in as they all vary state by state, you will prob never be pulled up if car looks tidy and not to low (less than 100mm lowest contact point to ground), but legally (insurance wise) could be a problem.