Don't bother...just something else to break or screw up.
You've already got the fuel-pump cut-out at 7000 or so (which I always 'hot-wired' around), and the ultimate 'rev limiter' - i.e. rod sticking outside the block - which rarely happens with the 1.8. Really stout motor, really stout bottom end.
The only bad thing you can do to a 1.8 is hit 1st while making the 4-3 downshift (or 2nd while going 5-4), and a rev limiter won't save you.