Q:

Suzuki Aerio '06 5-door wagon -- roof rack for factory mounting points

I've never dealt with roof racks of any kind in the past.  Not for Suzuki nor for any other car.  That's why I'm having a hard time finding what will work for my Aerio '06 SX (5 door wagon). 
I understand, that the product recommendations are very likely to be off-topic here, so the question is focused on How to find the rack that can be installed correctly (onto the designed mount points) and what to watch out for?. 
What I'd like to get ideally, is the roof bars(?)  that go across the roof and use the factory installation mounting points instead of any alternative system.  I am planning to put two 2x4s along the car on top of the bars so that I can transport a couple of plywood sheets from my local lumber store. 

Update.  My local Suzuki dealership was purchased by a competitor, so the staff is a bit less knowledgeable then they used to be.  The parts department employee told me the "native" crossbars have been discontinued by the manufacturer. 

A:

As you've spotted, you have factory fitted mounting points on the car.  There's a number of different versions of these (I'm not familiar with Suzukis to know which they have), but most suppliers of roof bars will supply most versions. 
Usually roof bars are sold in three parts - the bars themselves, the feet, and the fitting kit - the latter is the bit that's specific to your vehicle.  Any reputable supplier will have a guide which kits fit which vehicles - traditionally this was a big book in which you looked up your car and saw - "aha, I need fitting kit 'E', feet '3' and bars 'X'" - these days it's usually an online thing into which you put your car details or registration/index number and it looks it up for you.  For example, Halfords (a major UK auto supply chain) have a Roofbar selector tool on their website. 
Your best option therefore is to look for a local supplier (or an online one who ships to your area, but shipping may be expensive as they're quite big) with such a tool, either online or in their store.