My son is only 13 months and almost grown out of his infant seat. I intend to keep him rear facing so I am looking for a convertible seat. And want to use the same seat eventually when the time comes to forward face. My 4 year old currently is using the safety first alpha omega elite forward facing and his head slumps every time he falls asleep. I hate it! I was hoping to find the right seat so we don't have the same issue later on. I will have to buy 2 seats, one for each car, so I am looking for around the $150 price range. and preferably one that I don't have to rethread the shoulder straps on. thanks!
Are your 4 year old's shoulders below the top harness position on the AOE? Which model is it - the one with the 40, 50 or 65 lb forward facing harnessed weight limit? The top harness slots are pretty short on that seat, and the booster function does not provide a safe belt fit so that seat is going to be about at the end of it's life for your 4 year old very soon, if not already. For all those reasons, I would just pass it down to your 13 month old and put it RF of course, and get a new seat for your 4 year old. You can get a good combination seat (FF harness plus booster) that will have much taller harness slots and make a GOOD booster in a year or two when he's ready.
The only delimma is that the 4 good combination options are the Evenflo SecureKid, Graco Nautilus, Recaro ProSport, and Britax Frontier. The first two are in your budget at about $130, BUT neither have a no rethread harness and most kids have head slump when they're asleep in them. The last two are great for sleeping, have a no re-thread harness, BUT are over your budget at about $220. I would probably get one of each and you'll still within your total budget, and just put the Britax or Recaro in your primary car since I'm guessing that's the one where he sleeps the most, and then get either the SecureKid or Nautilus for your second car (or, an Evenflo Maestro which is pretty similar to the SecureKid except the booster function is much shorter, but it's only about $70).