Im recently purchasing a gasgas 300 txt pro 2005. The bikes piston has gone apparently along with the rings. Ive looked at videos of top end fixes on motocross bikes on youtube, but wanted to know if trials bikes are any different. And would i need someone to do it for me or would it be easier to do it myself?

Two stroke trials bikes are easier than two stroke MX bikes because they don't have power valves

I would walk away, theres plenty of other bikes around that arn't knackered. If you've already bought it i hope you got it really cheap as you cant take someones word that its just the piston & rings. I'd expect to spend a few £££'s on the other things that would need doing also.

It’s not hard to do mate. Just make sure you put a rag in the top of the engine as you lift the head so nothing can fall into  the engine. The rest is simple just take your time, As long as you know your way around a tool box you will be fine.