KLX/DRZ125 Big Bore ~ Mods

Have a KLX125 that I have upgraded to KX100 forks, swingarm, shock, rear wheel/disc brake. Don't use it a lot but once a year friends get together and have a pitbike race. Looking for some more HP out of this thing. Any reviews/leads on Chinese big bore kits (I believe there is a Suzuki 125 street bike that is popular over there that uses the same engine)? I seen bits and pieces of people that have done this but the threads were from 5 years ago or so. Also heard that Suzuki LT185 ATV top end will work on this, can anyone confirm this is the case? Can I just get the 185 cylinder/head and bolt it up? Any advice is appreciated, pic for attention...