you meant to say 6 years, not 6 months,
do share your experience after removing the CAT. I removed that 5 years ago when I bought my vitz, and I am still not sure if it made any difference or if i did the right thing. the good news is that I haven't faced an issue because of it (except the guild of hurting the environment)
Storm bhai doesn't reply to this thread anymore probably because of some stupid questions appearing on this thread over and over again.
as far as top speed and performance is concerned, it depends on a number of factors, I am listing some in no particular order
- tires (size, condition, pressure, alignment)
- engine oil (viscosity and condition): I use 5w-30 or 5w40 fully synthetic oils as recommended by the manufacturer, regardless of what people here tell me. using thicker oil will make a noticeable decrease in performance and economy
as far as plugs are concerned, I used ngk platinum plugs, i couldn't notice any difference in performance or FE, but they were like new when I eventually changed them after using 60,000 km in more than 4 years