I like SR's and CA's (I love the CA!), but RB's and I6's in general are just 10x cooler IMO. Personally, I like 4cyl turbo engines and all but sometimes they just bore me. I think 99% of that is due to the sound, just because I'm a sound whore.

Even if the RB26 had less power than an SR, I would still choose the rb just because it sounds so damn good!

4cyl's can sound good too, but IMO, they can never really sound as good as some i6's do.
Rb's are extremely heavy, so with a stock suspension setup, it's definitely going to throw the balance off a little bit. However, with a set of coil overs you could just corner balance the car and eliminate that issue. Of course it will probably be a good amount heavier than a similar car w/ an Sr, however that doesn't necessarily mean it's going to handle like a land yacht as some of those guys might have you believe. I say do whatever makes you happy and have fun with it!