Are there any general differences between OPAMP SIP packages and OPAMP DIP packages? Not so much the package layout, but in terms of distortion, losses, etc.
Generally no, it is the same physical die, just packaged differently. The only difference might be a slight variation in characteristic impedance, but it will be within the tolerance specified on the datasheet. At very high frequencies, perhaps 100s of MHz and beyond, the package construction becomes more significant.