Yes, but you have to have a crossover between the pre and amp sections. If you Onk can do THAT, the go for it. PS: if you biamp, the impedence is 8 ohms for each part. Only together does it drop to 4 ohms.
Finding a suitable external crossover is the big hassle in biamping.. and getting good results is another hassle. As for 'just considering it goofing around then biamping with your stuf would be an interesting exercise. As for 'better sound' with your stuff biamping the 1.6.. that is more problematic.