When I set-up my tank, I chose LED's due to how often bulbs needed to be replaced on T5's, etc..
I have seen a Juwel Vision 180 but never opened up the hood to see what space there was underneath. It would be a shame to lose its compact, yet contained look, just to add lighting... But that will be a personal decision for you to make!!!
As far as your scape, I wouldn't set it in stone, until you know for sure what plants will do well in your tank, and what won't. As your plants are new to you(still dropping old growth) having them easily accessible for trimming, and cleaning will be a benefit!
The ferts you chose should be made after you decide on lighting, as this will dictate what your plants will actually utilize. No sense in getting a comprehensive fertilizer regimen if it will only be feeding algae... There are some good websites that sell dry kits for PPS-pro, and EI dosing, which is much cheaper in the long run($15-20US for 2 years worth rather than a liquid that's $10 a bottle that will last a month or two tops).
And after those two decisions are made there is still the choice of liquid or pressurized C02 supplement. DIY C02 is out the window in a 180. There is a product called Metracide 14 available on Amazon, I don't have any expierence with it, but there are some members on here that do, and some good posts on how they dose it. I went the pressurized route with a 5lb cylinder. It's a bit costly at start up but lasts a while(got my first cylinder back in Febuary, and it hasn't dropped the pressure level yet). With pressurized you'll need the cylinder a regulator, a solenoid, a bubble counter, a check valve , C02 grade airline tube, a diffuser and lastly a drop checker, all said and done for me it was around $260 USD... So it is an investment, but increase in growth has allowed me to recoup some of those funds, by trading in some of my trimmings at my lfs! Theres a lot to sort out in a planted tank, but it's very rewarding to see the plants take off and the fish greatly appreciate it!
