Regarding the Krinkov I would say you can't beat the Tacamo parts:Also whilst I'm here, anyone know the best place to get a .67 AK-47 replica marker with the krinkov butt or which kit/marker combo work the best?
http://www.tacamopaintball.com/products/
and they should be available here through RAP4UK, which also has the option of a RAC4 Krinkov, but personnaly I would say go for an A5 or X7 based one.
http://www.rap4uk.com/SearchResults.asp?searching=Y&sort=13&search=krinkov&show=30&page=1
In addition watch the classifieds on http://www.ukscenario.com/forum/index.php