Pipe:Sprocket ?

[Pimpin400ex 15]

If I get an HMF pipe, will it be a good idea to raise the front sprocket to 16t?

[AndrewRRR]

That sounds like it's pretty tall gearing. It'll give you more top speed at the expense of acceleration (provided the bike has enough power to pull top end in 5th with that gearing).
Every tooth your raise the countersprocket is like dropping 2 teeth off the rear sprocket.