I need to replace the tires on my 2005 Outlander XLS, is it really necessary to replace them with "V" speed rating (P215/55R17)

I was looking at "T" rating which is good for a speed of 190Km/h (118mph). I will never drive that fast.

 

The T rating is fine. My 08 Outlander came with tires with a H speed rating (130mph) and I replaced them with T rated tires. However, it's very important you keep the same or higher load rating which is the amount of weight each tire can handle. If you're not sure what the load rating is for your OEM tires the place you buy the tires at can help you on this.