Are you looking at a 5th gen (fi, pre vtec) model?
There's loads about, worry not about mileage - 30k is about run in for these.
Get a HISS model if you can, they changed some bits on the 5th gen in 2000, you get stainless headers with a CAT, HISS immobiliser, automatic choke and probably some other bits I've missed. If you get an earlier 98/99 one you'll have to make sure the header pipes have been replaced with a stainless set so it's easier just to get a later model. The cat shroud can made it look rusty but that's just the cover, the cat and pipes will be fine.
The brakes are linked so feel a bit wooden to start but they're solid - when you use the front it applied one piston from the rear, and when you use the rear there's a delay valve which then applied one piston on the front, so when you brake they 'squat' rather than dive.
I've had no issues with my r/r and even killed a batter stopping and starting the bike in the eurotunnel customs queue, the dashes sometimes have issues so make sure all of it works, have a google to see that issue.
TBH there's not really much else to check apart from the usual stuff, find a nice, unmolested one sold by the usual 'older' gentleman owner of thse privately for under £2k - I had a choice of 2, my one with 23k and in very decent nick, a 2000 model, or a earlier non HISS model with 35k but it absolutely mint condition, 1 owner. Both for £2k. If there's none about one week, wait a couple of weeks and there'll be a couple more for sale.
Oh and I hope you like red!!
Seems like about 75% come in that colour. And of course if it doesn't have an exhaust get that before anything else
The straight cut cam gear whine will be louder than anything else, you need a nice V4 burble to go along with it