i am kind'a new here...so i would need some help []
howerer i have some plans for extra 300 L... but unfortunatly it is designed for 8ccm... and my "storage" has only a 4 ccm OS LA & 6,5 ccm LA . i was thinking to buy a kit from Great planes ... but ive heard its kind'of heavy though...so 6,5 cannot offer enough power, so has anyone any suggestions? plans maybe? or should i go with GP's 300 extra with my 6,5?

(im on a budget, so i can't affort a new engine ) please help!
Have a nice day, Marco