It ain't worth it.... and it will still be an older C27. Besides, tillers are cool. Wheels are unnecessary for boats under 29 feet... they also take up a lot of cockpit room and access on smaller boats can be a problem without redesigning the area. Converting to mid boom sheeting is more reasonable, even though the cost of a bridge and the need for additional purchase hardware may surprise you.
If I were wanting to spend a bunch of money on my Cat 27 (oh, I did that already) I'd put it into new canvas... i.e. a dodger... hardware, such as ST winches, clutches, stanchions, portlights, etc. and electronics.