do window ac units leak smell?

For mini splits I recommend Daikin and Mitsubishi, but they are usually at least twice the cost of that unit. From what I just looked up, Blueridge seems to be a re-branded Gree. These are relatively good units for low-cost options. Keep track of how your existing unit does with the heat and base the tonnage on that. You can over-size just a little if you are planning to possibly add more heat load later (more lights, etc...). But bigger is usually not better...properly sized is always better.

Seems like a great price and you have lots of time to watch for sales.

Oh, and if you are going to diy the install...remember you have to pull a good vacuum on the line-set. I also always insist on pressure testing the line-set with nitrogen to ensure there are no leaks...flare fittings suck compared to brazed line-sets and you want to ensure that you don't have any leaks.

Will do, I was going to run 6 lights, 4 in flower, two in veg... So 18000 seems like its not enough, 24 seems right, but then I consider I'm far up north and in a basement which are factors...

Any suggestions?

Sorry, I can't help you there. I've never done a heat load on a grow room. But I'm sure there are lots of people that can help if you give them all of the details.