AR Blue Clean 1800 PSI (Electric-Cold Water) Pressure Washer With Hose Reel & Turbo Nozzle

You need to have the pressure washer set at the lowest pressure setting on the vario lance. Also see step 13 on page 7 of the OWNERS MANUAL. The detergent should only be about as thick as water or it will not be able to pull properly.

The performance will be closely to the same. The SS has nicely upgraded accessories which will last longer and easier to use.

Since it is an M22 connection, you can purchase adapters to make this possible.
You will want to get one of model D10035 for your gun. You will then want to purchase anywhere between 2-3 of the adapter D10037. Purchase two if you just want to do your standard lance and foamer, purchase 3 if you would like to make your turbo nozzle a quick connect too so you don't ever have to thread them together again.

The MTM Hydro foamer attachment will connect to the AR390 with no problem or any adapters needed. The foamer attachment comes with an M22 threaded adapter that will connect to the trigger gun just fine.

Using an extension cord is not recommended with electric pressure washers. However, if the situation requires you to do so, you can use a 25' cord as long as it is an outdoor rated 14 gauge cord. You may increase the extension cord length up to 50' but then you have to increase the size of the cord to a 12 gauge cord.

Yes the new AR390 does comes with a 30' hose versus the AR383 comes with a 25' hose. However, both hose reels are designed for storage use only. With any residential grade pressure washer that has a hose reel installed on it, you should always remove the entire hose from the reel during use. This will prevent any possible blockages within the hose that would cut down on the pressure.

In regards to the psi difference, more than likely you would not notice the difference. However, there is definitely a difference in pressure. Typical pressure from a garden hose is around 70 psi, just for you to compare.