As for you saying this ( latch max is 48#s including child and seat weight)...that is incorrect. It is up to a child weighing 40lbs...period. Doesn't include the seat weight (the regent is like 30lbs, but can be used to the weight limits of your latch according to your vehicle guidelines)
First, the safeguard go has to have a tether anchor, so that is out for your 99 accord unless you get it retro fitted (part number is 82410-SE3-C01). Plus, there is NO side impact protection AND when he falls asleep, he has nothing to rest against. It will only harness to 65lbs
The Regent is the tallest, highest harnessing weight seat on the market, but you must have a tether anchor for it. I have 2 Regents and absolutely love everything about them, BUT they are HUGE seats. Babies r us has them in stock, so try it out in your vehicle.
The Radian 80 is a convertible seat that will now RF to 35lbs and FF to 65 or 80lbs. They have been known to be incompatiable with a lot of vehicles, so if you have a store near you, try it out.
There is also the Graco Nautilus that will FF to 65lbs, then booster to 100lbs. At walmart for $150--NICE tall harness slots as well..
Rumored that Britax is coming out with the Frontier which will harness to a weight, then booster. Nothing coming from Britax...yet, just rumors.  |  |  |  | SafeGuard - Click for more info |  | Indiana Mills and Manufacturing (IMMI) is SafeGuard’s parent company, and has been in the business of developing and manufacturing quality safety systems for every facet of the transportation industry for over 40 years, covering everything from the heavy truck and agricultural industries to child seating.
IMMI has a world-renowned reputation for creating and promoting the highest rated safety harnesses and restraint systems available today, from integrated child seats in production vehicles to campaigning for increased use of safety harnesses on public transportation systems. Based in Westfield, Indiana, SafeGuard has been creating and testing essential components used across the child safety seat industry through their state of the art crash testing facilities since 1961. The SafeGuard and SafeGuard Go are IMMI’s first direct foray into the child safety seat market, and the results are simply outstanding. No other car seats or boosters are designed with as much attention to structural integrity, ease of installation, and total child safety. This seat has been subjected to the most thorough and extensive testing “ever conducted in the industry”: virtual prototyping with computer models; rigorous front, side, and rear impact crash testing; and environmental testing in a range of climates and road types. | |  |  |  |  |
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