Kangaroo Engine cleaner is a relatively cheap product costing about 550/- but is an effective one also. However, if you want to thoroughly clean the engine bay and suspension a complete can is going to be used. But possibly, two or three applications could be extracted easily. Meguiar's Cleaner Wipes, are, well self explanatory. One wipe is enough for one application of interior detailing. And yes it works like a charm. However, there are equivalent and maybe cost effective options out there like Sonax Cockpit Cleaner (Matt Finish) and Turtle's.
Liqui Moly Speed Tec is something you will have to use to assess yourself. Many people do not believe in additives. While we can't question the Research and Development of Liqui Moly, however, lack of accurate lab tests and inability for the Driver to measure the real life difference, I guess we will have to take Liqui Moly's word for it. However, being very critical of judging any performance gains, I did notice smooth acceleration and crawling in lower gears. It is NOT A MUST HAVE. Fuel System or Injection Cleaner are the better candidates for your cash.