I had a Kougar!! nice plane. To get it fast you need to improve engine perf and decrease drag.

to decrease drag install retracts and seal up hinge gas.

to improve power and keep to a 50 size engine weights try a WEbra 50 or better still 55GT esp with a tuned pipe!!. this shoudl give you all the perf you need. Teh jett will be even better but cost a lot more.

You could also try higher nitro - a the exp of engine life.

Cheapest improve enginewise would be to buy a TT pro 46.