My SE does everything that the Harrier does but smoother. The roll axis is much more stable.

Taking the wingtips off had no noticable adverse changes. It's not great, but it's better. Just be careful when you cover the wingtips, the end ribs are very light and will bow with any heat to the covering. You might wanna glue a balsa support plate to the end.

I just cut the whole tip assembly so it was flush, and trimmed the ailerons to the same length. There's a rib in line with the end of the wing there, and I just cut it there.