The only cheaper priced unit that works pretty good is the Devils own Alky system, but there cannot take 100% methanol as the Alky control system can.
http://www.alcohol-injection.com/en/19-universal

http://www.ebay.com/itm/Devils-Own-Unive...fbcd63f&vxp=mtr

While data logging running 25 psi of boost pressure I have recorded manifold air temps of 59 degrees F when injecting 100% methanol while using pump 91 octane.

I believe all newer cars have knock sensors installed from the factory.

Adding a knock sensor to a turbo charged engine in my opinion is highly recommended because you cannot always hear detonation where as a knock sensor will pick up knock & retard your timing accordingly.

Snowman never installed any knock senor/timing retarding devise & I am most positive he could never hardly ever hear his engine detonating as he ran an open pipe exhaust system with no muffler.(TOO LOUD to hear detonation)

If you ever get a chance to data log an engine that has a knock sensor, knock retard light/s, you can & will see an engine will knock/detonate & you cannot even hear the detonation, a J&S safe guard system is highly recommended & my has saved my Syclone engine many times.

Certain "winter" windshild washer fluid is the better one to use as it should have methanol in it.
Straight distilled water is OK but does not & will not make as much power as injecting 100% methnol, plus adding too much water does not burn & will put out the spark more so than adding alcohol.

It is safer to run a 50/50 blend or 60/40 methanol/water.
Plus it is cheaper to use a water /methanol mixture,, if that is a concern.

MBHD

12 port SDS EFI