I Found an RO/DI Water Filtration System I Want, Is it a Good Set Up ?

I know NOTHING about Reverse Osmosis systems, never used one. Someone on here about a year ago recommended The Filter Guys and I've had my eye on one of their units for a long long time and I've made my mind up to order it, but there are some add-on accessories you can pay extra for and I'd like to know what those accessories do and which add-on accessories I should get with it.

I want the $135.00 - OCEAN WAVE FIVE STAGE 75 GPD RO/DI

ADD ONS: PRESSURE GAUGE KIT - $14MEMBRANE FLUSH VALVE - $10 RO BYPASS VALVE - $12 DUAL TDS METER - $35 DUAL DI SYSTEM - E-MAIL FOR PRICING AUTO SHUT-OFF - $8 100 GPD FILMTEC MEMBRANE OPTIONAL - $5$14.00 - CHLORAMINE FILTER UPGRADE -TWO FILTER SET

I'm only going to use this system by running a garden hose into it outside as I need it. Landlord's a dickhead and won't allow any plumbing or water lines to be touched.
I've got well water that's real hard. I'm a soil grower but I still want an RO system.
Do I need the Pressure Gauge kit add-on for $14 ?
Do I need the Membrane Flush Valve add-on for $10 ?
Do I need the Auto Shut-Off add-on for $8

Already have a TDS-PH meter , I'm just wondering about the importance of those 3 add-ons, all I want is RO/DI filtered water as close to ZERO as I can get. My well water averages around 190-200 ppm.
From what I understand, a Pressure Gauge is needed if your using an accumulation tank and since I won't be using a tank, I don't think it'll be necessary to pay extra for that. The Membrane Flush Valve I think just prolongs the life of the filter ? I think $10 is a small price to pay for that add-on. The Auto Shut-Off....I have no clue what that could mean, possibly something that's used with a tank ?

I think all I should get is the Membrane Flush Valve ($10) and the 100 GPD FilmTec Membrane ($5) , that'll bring my total to $150.00 and with shipping it will be $182.00
I can get an adapter for a water hose at Home Depot for this I think ?
Am I missing anything, would this be a good set up? Does anyone have any reviews on the quality of the Filter Guys RO/DI systems? I've read a few reviews on 2 different aquarium fish tank sites and everyone said they have quality made stuff and good customer support.

http://www.thefilterguys.biz/ro_di_systems.htm

Why don't you like your water now? A ppm of 190-200 is great, and well water contains a lot of micronutrients those babies need. Is it overly sulfurous or something that makes it bad for growing? You already have the advantage of not having to deal with chloramines like the rest of us tap water users...

I'm moving back to the city sometime in 2011, I also like good drinking water, and I'll always be an organic soil grower but I'd like to do some DWC grows too as I have 3 reflectors and 3 ballasts. I've wanted an RO/DI water system for a long time. I'll be moving before the holidays this Fall and I want to go ahead and get a good RO/DI system.

I gotcha...just remember with an RO system you are more than likely going to have to supplement with cal/mag.