agreed~~

its cheap for 14-15 size... 17's is overkill...
i never see such upgrade on the wiper intermittent options in the trade.

what performance you're referring to? it depends on what you wanna achieve in the first place?
yeap.

Instead of modify the wiper with intermittent function, how about replace a good silicone wiper. That will enhance the visibility during heavy rain.

If got budget, go for PIAA brand. No regret to own it for the past 5 years. Still tip-top condition.

Eneos got sell PIAA product. Price from RM79 to RM260 depends on the range and size you choose.

from your tone:
1. Sound proof
2. Entry Level Ice
3. Leather seat
4. ARB
5. Exhaust system

My suggestion:
1. Sound proof --> highly recommended to proceed with full floor + rear boot. Next, is wheel arch and 4 doors. Around RM3k.
2. Entry Level Ice --> the range is too wide; from RM1k to infinity.
3. Leather seat --> optional, cost around RM1.8-2.5k
4. ARB --> recommended to reduce bodyroll, much better handling at corners --> cost around RM400-550.
5. Exhaust system --> don't touch if you're sending in to those AhBeng workshops

hope the above helps.