Eibach 20444.212 with stock retainers and port sizing

[3literpwr]

Gents...

Can anyone comment on using Eibach's 20444.212 springs with stock SC retainers? Also, I am at the point where I need to make a few decisions on port sizing... My build will consist of 3.0, JE 10.5:1 pistons, 46mm ITB's, Stand alone ECU and DC60 cams with a rev limit of 7500 RPM... My plan was to port the heads to 40mm intake, but I am unsure about the exhaust port... 38mm?? As of now I have some 1.5" SSI units, but I plan on selling those and going to a 1.625 unit. The car will be on short gearing.

Thanks
LP