If your OEM clutch is dying, I'd suggest you "up"grade to an organic clutch or something else in the non-OEM "heavy" duty range. I personally enjoy the drive alot more in my DC4, and it's basically stock still.

I take it you want to increase performance/speed/torque all around, so removing the 18"s is a great start. Revert to stock 15" VTiR rims or similar well weighted 15"/16" rims and the difference in handling and speed there alone will amaze you.

You might want to examine a decent intake, maybe a quality exhaust etc.