Hi Tunin, welcome to MV...
Hard tires, ride longer.. but have less traction. Soft tires wear out fast but have great traction. So you have to find a tire, that has a good balance of both, you do not want to have to change your rear tire ever 2,000 or 3,000 miles, but you do not want to slide to a stop at every intersection, or have the scoot slide out from under you on a sharp corner either.
There are a lot of threads here about tires, and for the most part they will most likely confuse you.
As there is no overwhelming winner as to which tire is the best. Different people want different things out of their tires. I do not race my scoot on a track so I want tires that last , would love to find some that I can get 10,000 miles out of a rear 10inch tire, but then I would like to have 3 or 4 million dollars handed to me, no stings attached too... Neither is about to ever happen.

So hopefully someone can recommend a tire you like and will enjoy having on your scoot. I have heard good things about the Heidenau K61's, I just ordered a set for both my scoots and will change them out as needed. The Micheline Pilot city and sport get good reviews too. I think it is the Pirellie's that get good reviews and the Stock Sava's that no one likes because they wear out so fast.
Now as for your original posts, there are all kinds of things you can do to improve performance, just remember they are all going to drop your mpg. So read through the reviews and follow ups on each one. Individually they do not offer much improvement but I think those that have done several of the upgrades have gotten a nice performance boost, but not sure if the mpg drop was cumulative or if it stopped being affected after a few of the changes.