that's highly variable and depends a lot on you (how you're going to sell it, how much you ask, condition, etc), state regulations (will the person have to have it inspected immediately?), and local buyers, neither of which we can comment on.
fall and tax return season are good times to sell, you have that going for you right now.
in general - of course it matters. the same reason ($) you don't want to pay to have it done or do it - is the same reason most buyers will move on, hesitate, or negotiate more.
if you're trying to get top dollar - then it's going to matter. people paying top dollar don't wanna dork around. a busy doctor doesn't want to juggle a car - they wanna buy and drive.
if you're just trying to move it and asking an average or lower end price for your area - it may not matter....depending on the general Subaru market, state inspections, etc. friends bought a car last year - paid pretty decent cash for it (nice, low mileage, H6)...but it had a broken boot. i told them i'd fix it for them for free. i wouldn't consider that normal but if there's a mechanically inclined person involved a $25 part isn't going to scare them. it'll make most people think though...and it's a $200 repair for the average person.
you'll definitely loose a certain percent of buyers, but that may not affect price.
so again..highly variable and may or may not matter depending on a lot of variables.