Wetsounds upgrades

Checking in to verify some research before ordering.

I sold my boat a few years back and kind of got out of it. A few of my friends bought boats this year and we are getting ready to do a wetsounds upgrade In one of them. Wanting to make sure I'm recommending him right since its been 6-7 years since I bought my stuff.

420BT
2 pair rev 10
SD2 to run tower
3 pair revo 6. He will be removing 3 pair of kicker 6.5
he wants to save a little on the in boat amp What do you recommend. Syn4? Arc 300.4?

I recommended probably 2 L16 6v for him. What do you guys say? He doesnt want to go all out but he wants it right with a reasonable budget.

I recommended something like 1-2 DC level 3 12's for woofers. What amp do you recommend to run those these days. Need about 2000-2500w

Ofc speaker and power wire from knuconcept along with distribution blocks and fuses.