Booster seat recommendations

Looking to upgrade from a full on car seat in my car to a booster seat.  Its getting increasingly tight for him to navigate getting in/out of the car with the bulkiness of an oldschool car seat back there.   FWIW, he's 5.5 years old and ~46" tall.

The thing about the car seat though, is it uses a 5pt harness and he can buckle that himself.  In my experience with booster seats, many rely on using the car seatbelt which is a lot harder for a kid to do, esp. in my car where the receiver opening is flush with the top of the seat.  I think he could probably deal with this last part if he didn't also have to feed the belt under/over whatever routing steps are needed.

Any recommendations?

The booster seats we have used have little armrests, but other than that you just feed the belt across your lap like you normally would. The hardest part, as stated, would be actually plugging into the receiver.

Linky

Look for something like this.

The last seat you'll ever need:  

Grows with your child from
forward-facing harness (22-65 lb)
to highback booster (40-100 lb*)
to backless booster (40-100 lb)

We have one of the black ones I linked to and we have one that matthew linked to.  

The cup holders suck on the black one.  The cup holders are better on matthew's

One like this had the cup holders of matthew's and still offers high back but only allows for use of the car's seat belt.  

The nicest thing about the high back booster is it has a guide/holder for the belt at the neck to keep it from riding too high.  The side impact protection is nice too.  If nothing else, it's a head resting place for sleeping while sitting. 

Mine looks like the black one you listed, but gray.  I think if I convert to 'high back booster', it just means removing the harness and using the factory belt.  Its still pretty bulky.

I'll have to give it a shot with the bottom booster only.  I think when I do that it also removes the latch connectors which is good, because being able to easily pick it up and move it on a whim would be nice.

Honestly, I would prefer no cup holders.  They are just a place to collect child refuse, and add unnecessary bulk.

Recaro. Might be s struggle nowadays, they've left the us market iirc. 

Ok, so as best I can decipher, it sounds like you have a harness-to-booster seat and are looking for a 2-in-1 (high back and backless) booster. I did find that while our harness-to-booster was great in harness mode, it was nowhere near as good as a 2-in-1 as a high-back booster due to routing the seatbelt through all the massive side bolstering dragging on the seatbelt. Dedicated 2-in-1's don't have this problem. I do think you sound too caught up in convenience though. 

I would not consider going backless booster for at least another 2-3 years yet. The high-backrest serves dual functions of providing body support as well as belt-positioning.  Besides, once YOU route the seatbelt through it correctly, any kid ready to ride in a high back booster can learn to buckle a regular seatbelt. My daughter struggled with her 5-point all the way until she switched to a 3-point, but quickly became quite good at using the 3-point with her 2-in-1. Having the buckle receiver set into the seat actually helps stabilize it for them vs the loose floppy ones. Especially once we switched to a dedicated 3-point booster from the harness-to-booster that had a lot more drag on the seatbelt.

Also, don't be too quick to get rid of the LATCH connectors on a high-back booster either. Even with LATCH 2-in-1 boosters aren't hard to uninstall and reinstall. Sure if it's a seat mostly used for occasional short trips, get something extra light without LATCH. But if it's a frequent and longer drive use seat, you'll probably want something a bit sturdier and more comfortable, which adds weight. Now everybody talks about how all LATCH does is allow you to not have to remember to buckle the empty seat in to prevent it from flying around with no kid in it. But something nobody talks about is what actually happens in an accident. LATCH holds the weight of the booster to the car, rather than it adding to the forces pressing your kids body into the seatbelt. Think about the extra forces on your body if you got in an accident while sitting in a 40 pound seat that wasn't secured to the car in any meaningful way other than through the seatbelt with your body sandwiched between the two. 

FWIW, we looked mostly at the Graco Turbobooster LX and Chicco Kidfit for our main booster. We went spent a little extra to go with the Kidfit because it felt noticeably more comfortably shaped and padded for our daughter. It's LATCH'd in, but is not a big deal to switch to other cars occasionally either... Unlike our old 30 lb harness-to-booster was. However, our secondary use and more frequent for use in other peoples car seat is an Evenflo Big Kit Sport which does not have LATCH but is very light and also fits well in more sportily bolstered (narrow) rear seats, which my 128i needs.

Bump. In the market now. Would like a high back harness booster. Low profile would be a nice benefit as kiddo is pretty tall and my wife currently can not see out the back of her rig with him in the car seat.

Suggestions?