The time/cost to rebuild a Tiger engine is a waste. Best way to get power out of an N/A is to get it (or a local motor) rebuilt by a pro. Get all your gap clearance issues taken care of, port, polish, new seals, header+exhaust, good coils/plugs, and some fresh air for the intake. Sleeves are a good idea.
And #1 is a proper ecu/tune.
(I bought a tiger 13b-rew years ago and it was shit, sent it to Mazmart to get rebuilt, it was pushing over 460hp after)