Go to your local hardware store and get Grade 8 bolts, they're like a goldish color. I'd say 3/8 x 1 1/4. Should work perfect, but put your bolts in from underneath and use either nylon lock nuts or lock washers with standard nuts so you dont lose em' goin' down the road. I would probably go with the one from sgstyling since it states it's actually for the aveo, the lanos one should work perfectly but you never know. Idk if anyone has actually ordered that one for an aveo yet.
I don't know about the Lanos bar working perfect... (after holes drilled) Have you seen a picture of it installed? Also, if you do go that route and the off chance it fits, your bolts should face down so if you lose your nuts, the bolts remain. Yes on the lock washer or the fishing line trick or self locking nuts. 3/8 is nice, you can use a 14mm socket on it. Grade 8 would not be necessary for the bar, though as a general rule you should use grade 8 for suspension parts.
the SG Styling bar works with the two holes next to the strut top. Pop your hood, you will see them.
When I contacted this company. They told me that I would need to purchase the Lanos Bar, but Specify that I was ordering for an Aveo.
They had a different bar for the Aveo.