Right seeing as Fontyyy hasn't taken the bate I'd better step on to the soap box in defence of the MC28.
If you like to look and the concept of the MC28, the go get it. They aren't that difficult to derestrict and to be honest I was plenty fast enough with the std card, race pipes and an airbox tweek. The thing about MC28 ownership that that you have the last generation of NSR, with the trick c card ignition and s. sided swinger. I see Matt's point in fitting a pro-arm and fairing to a MC21, but let's face it, it's the smartcard ignition system that everyone asks about. The expense is in buying the HRC card in comparison to sniping a few wires on the MC21, but seeing as you're already prepared to pay alot more for the MC28 in the first place, a few extra notes is neither here nor there.
Now Matt and Steve are performance junkies, and that's cool and I freely admit that it might not give you the highest power output compared to a '21, but for the road...it's near as damn it and I wouldn't want to eek the nth degree of mojo outta my street bike cos it'll only go pop.
Here in the UK, MC21 are 10 a penny, the MC28 is a bit special and this is represented in the prices. I'd go with the MC28 and be happy in the knoledge that you ride a great and special bike that isn't like every other CBR/GSXR/ZXR you meet at the local roundabout.
Looking at the pictures it hasn't got the correct bodywork if it's a true '97 SE. Should be those tracksuit purple and yellow colours. Check Jamie's NSR site for pictures.
Oh yes I should mention.........for performance I went and bought an NF5.