Alright, it seems i made everything work without the 451 patch. Extreme textures no longer lag too. Must have been a glitch.
So what i did so far is install UT, replace the opengl driver with this one:
http://www.cwdohnal.com/utglr/
Apply the regfix so i can run umods:
http://unreal.co/downloads/index.php?dir=tools/&sort=size&order=desc
Then went into the ini of the game and under opengl i pasted the following (copied from a tweak guide. Didn't check the individual options yet to see what they actually do, but hey, it works):
Translucency=True
VolumetricLighting=True
ShinySurfaces=True
Coronas=True
HighDetailActors=True
DetailTextures=True
TruFormMinVertices=0
TruFormTessellation=3
UseTruForm=False
ZRangeHack=False
AAFilterHint=2
NumAASamples=0
UseAA=True
RequestHighResolutionZ=True
MaskedTextureHack=True
FrameRateLimit=120
SwapInterval=-1
UseVertexProgram=False
UseCVA=False
UseMultiDrawArrays=True
TexDXT1ToDXT3=False
DynamicTexIdRecycleLevel=100
CacheStaticMaps=False
UseTexPool=True
UseTexIdPool=True
UseSSE=True
BufferTileQuads=False
BufferClippedActorTris=True
SinglePassDetail=True
SinglePassFog=False
ColorizeDetailTextures=False
DetailClipping=False
UseDetailAlpha=True
DetailMax=0
RefreshRate=0
MaxTMUnits=0
NoFiltering=False
NoMaskedS3TC=False
MaxAnisotropy=0
UseTNT=False
Use16BitTextures=False
UseS3TC=True
UseAlphaPalette=False
AutoGenerateMipmaps=False
UseTrilinear=False
UsePrecache=True
AlwaysMipmap=False
ShareLists=False
UsePalette=True
UseMultiTexture=True
UseBGRATextures=True
UseZTrick=False
MaxLogTextureSize=8
MinLogTextureSize=0
MaxLogVOverU=8
MaxLogUOverV=8
OneXBlending=False
GammaCorrectScreenshots=False
GammaOffsetBlue=0.000000
GammaOffsetGreen=0.000000
GammaOffsetRed=0.000000
GammaOffset=0.000000
LODBias=0.000000
Now, after installing the oldskool230 as well as the oldmodels umods, i installed this modded version of the Na Pali expansion:
http://www.unrealsp.org/forums/viewtopic.php?f=4&t=2187
But before that i copied all of the folders from the original game (Maps, Music, Sounds, Textures) into the UT folder without overriding anything (not sure how much i need to actually run the original game inside UT. I copied everything just to make sure). I then copied over all the files from the Na Pali Ultimate Edition. Included in this mod there is a bat file which loads the game with the Unreal Gold menu and recognizes all the map packs you have, including the original unreal and every map pack made for it (tried a couple, they all seem to work). I then applied the HD textures, overriding everything.
So voila, everything seems to work inside UT and i even get the original golden menu to boot. The HD textures look wonderful too (DAT colored lighting indeed). The modders did a good job maintaining the look of the originals.