hmm. would use new rings dude! and then rehone the bores (can you even do that safely with the crank etc in?)
its an idea tho, apart from i simply cant afford it mate, i am struggling to get 150 quid! plus the mot and tax are up next week & end of month
this way i get very nearly the same power and its a 10 minute job for 150 quid, it really does make bhp/£££ sense!
doing the 215 job would give me about 2-5bhp more and cost 5 times as much assuming you mean get even wilder cams which will cost me, or just the piston work and rings & rebuild bits would be over 150 alone and give me no gains over the standard.
this way i can also go for high comp intruders and adj pulleys for more torque at a later date.
plus theres the fact hardly anyone runs this setup so its a bit different innit