Ordered secret jardin dr60 need help seting up

So I ordered a secret jardin dr60 today and a 2' 4 bulb t5 setup. I am setting this up in my garage, temps get pretty hot during the summer(so cal). I will be venting the tent out to the outside of the garage through a old dryer vent. I am going to pick up 2 inline 4" fans and a carbon filter, 1 fan to vent the hot air out to the side yard and filter the stench out(through the carbon filter) and 1 to bring cooler air into the tent. Does that sound like a proper setup? I would appreciate and advice on the ventilation setup.

I am shopping for a hps light setup for flowering, I'm thinking 150-250w hps would work fine for flowering. I see a lot of growers recommending a 400w hps with a dimmable ballast for this size tent(2x2). What is your guys options on lighting? 150w, 250w, 400w?

Also is it possible to hang the carbon filter on the outside of the tent so I don't lose verticle space?

Yes it's possible, but not probably. if you hang it outside you'd need to cover the sock and be sure ducting was sucking air from inside, and not over the sock before it took air into it..... If you have a filter thats open on both ends it would be easier to do.

Same setup (in garage), 250 hps, inline extraction fan outside the tent but carbon filter inside sucking air out .
I used the 2 lower holes for inlet and a oscillating fan under the plants for air circulation. My question:
can I turn off the extraction fan when the light isn't on (I mean living the light and extraction fan on the same timer 18 x 6).
When the light isn't on, I would just leave the oscillating fan going inside ??
Any input welcome